When I was using my VeraPlus it as accepted that if a ZWave device was going to be disconnected for an extended period of time it should be unpaired. Else it could make the Zwave network unstable.
I would assume the same would be said for Hubitat?
A missing device Isn't itself going to cause any problem. The radio stick, the USB stick will know of it and will periodically try to "speak to the sleeping device," That causes extra traffic on the network, but a) aren't large messages and b) are rare, time wise. Perhaps Vera had some blocking built in. (Blocking where you have a resource that must be used one at a time, like the Zwave Radio, and a block is programmed to enforce one-at-a-time.) It's a time honored mechanism but is fraught with pitfalls.
In other words, it MIGHT be a very Vera specific caveat. Might NOT be also, but I have had months where I've had obsolete devices in my ZWave stick and the physical device sitting in my "well this is useless now" box. No sign of a change in stability when one day I decided to clean that up.
Thanks I have a FIbaro RGBW I'm waiting for @mike.maxwell to finish up the driver. I gave it a shot but this driver is not for the freshman groovy coder.
I have a couple of Z-Wave switches not currently powered. All you have to do is a Z-Wave repair and it will not route any device to the switch if it's a repeater or in case of a sensor. I don't seem to have issue bringing back.
Zigbee is a little wonky for me. Some I re/re the battery and others I have to reset/add but most will not have issue.