We do this all of the time, with locks, thermostats, garage doors, etc. Any device can fail, even a 'dumb' humidistat or the humidifier itself. One has to assess the risks of everything one automates. Yes, Hubitat can fail too.
I can think of a number of reasons that having the humidifier automated could be a good thing, including for example, being able to turn it off in the case of a water leak.
I have mine automated for three reasons. (1) the internal humidistat isn't all that accurate and measures humidity only at the dehumidifier, not at the other end of the room. (2) the dehumidifier has an overboard discharge pump that goes directly outside and if its freezes it will back up, with unfortunate consequences, so I don't turn it on if the temp is below freezing. (3) if it leaks for some reason there's a water leak sensor nearby that will shut it off.
not if you use the honeywell therm that can control it.. second when it is below freezing is when you need the humidifier the most.. the colder it is the dryer it is.. i got rid of my outdoor water discharge years ago and go into a drain pipe directly in the basement.
You're right about needing a humidifier most in the cold weather, but my automations are for dehumidifiers. In the cold New England winters the basement is warm and dry because that's where the boilers are. It's only in the hot and humid summers I have an issue. And though I do have a drain pipe in the basement it's several rooms away. That would be a long discharge hose! This one is right by a casement window, so it's a short run and well within the lift capability of the pump.
interested i had problems finding a dehumidifier that works when turned off and back on.. i finally gave up and just left it on a switch (when the house was empty) so i could turn it off if it ever got too dry but it never did. my run for my drain is long too about 1/2 the house and probably above the lift capability for the pumps but never have had any issues.. i do but bleach in the pumps twice a year because i have had issues with them gumming up and causing failures that way..
I have an all metal one for the steam humidifier as it is required to have a very high temp rating due to the discharge when it decides to empty the tank.. i do have 3 leak sensors around the furnaces because of this. and one of the washing machine hoses and a hot water tank that both let go at one point or another.
Oddly enough mine are Amazon-brand dehumidifiers. I have two such setups. I just leave them in the constant-on position with the fan on high and let HE do the rest. I use an Aeotec multi sensor to control the lights in the rooms as well as measure the humidity, ST smart outlets to turn them on and off, and ST water leak sensor next to them. They are set to come on if the humidity rises above 55 and turn off when the humidity falls below 50. I have an alert if the humidity continues to rise above 60 but that has only happened a couple times.
I also have sensors next to both boilers, next to the washing machine / set tub, under the very first forced hot water radiator in the system, under sinks in the bathrooms, etc. The only water leak I have ever had was when one of my boiler's auto-fill mechanism got stuck open. It filled the radiator system with water and they all started to drip. Ironically if the opposite had happened - the fill valve had failed OFF - I would have been OK (though chilly). Since the first radiator in the system is the one to overfill first, that's where the water sensor is. Of course it went in after the issue happened 
I don't understand your comment. A typical installation would involve connecting the air proving terminals of the humidifier to your furnace, in order to ensure the unit is not running when the furnace fan is not running. Beyond that you just have the two terminals in the humidifier that you could control with a humidistat or Hubitat.
How does controlling this with hubitat result in any more chance of screwing up a house than controlling with a humidistat? Either one can fail and it is somewhat easier to include a fail safe with Hubitat control as opposed to Humidistat control. And if your smart thermostat has built in humidity control, there is zero increased chance of damage and you simply gain more control options.
Thanks.
I can't get it to control the lights.
That must be frustrating.
Have you read the hub documentation?
Reached out to support@hubitat.com or created a forum thread to ask for help?
Yes. At this point, I wouldn't trust it for any mission critical control.
I am sorry to hear that. If that was my experience, I also would not be letting my hub control my humidifier. As it is, my hub either controls or is integrated with a host of "mission critical" devices. Door Locks, Alarm System, Furnace/AC, Smoke Alarms just to name a few.
I had (still do) it controlling my garage doors using the ST presence sensor. After one of the recent updates they were all opening and closing repeatedly. And now, light automations aren't working right for me. So, I'm a little sour right now.
I guess my point is you have to think about what would be the consequences of hub failure. And also, don't willy nilly apply an update to a hub that is working.
If it's just a matter of flipping on/off light switches, that's one thing. But, if it's a matter of HVAC failure in winter on a country house that's 200 miles away, that's another.
LOL, I hear you. I was using a custom driver for my Honeywell T6 zwave thermostat. Everything on my hub and on the thermostat is set to Celsius (I live in Canada). After the 2.2.4 update the custom driver showed everything in Celsius except for the heating setpoint that was 73 degrees (that would be the conversion for my Celsius setpoint). Couldn't figure out why it was getting so hot in my house. Switched to the hubitat driver and all is well.
Can't remember...did you put in a ticket w/HE support to get more assistance w/this? @bobbyD /HE support should be working w/you directly to figure this out.
Yep, he is. He was going to talk to an engineer about it.
It's not like I don't want to incorporate it:
Just now, I'm getting pushover notifications that the wood insert is >700F. This means I have to get up off the couch to do something about it. The fan is still local control though. I wouldn't trust the hub for that, unless there was a good local backup.
What idiot wrote that driver.. Oh wait.. It was probably me 
I bet you wrote both of them.
Download the Hubitat app
