Sorry if this isn’t the place, but since getting hubitat I’m redoing all my switches.
I tried to ask on Reddit but I got “add on, means add on dumb @$$”
I assume that’s a no? But id rather ask here before spending all this $. Btw, these are on clearance for $10, so 2 dimmers is cheaper than a dimmer and an add on
Contained in the product description within the link you provided:
Can control a single light switch or up to 5 different switches with a single command (GE add-on switch required for multi-light control, sold separately, item number 650030)
Yes. Some brands of z-wave switches can be wired to use a conventional 3-way switch in a 3-way or 4-way configuration. Other brands require an add-on switch that signals via the traveller wire. And I think there are some where the add-on switch signals wirelessly (could be mistaken about this).
Anyway, if you go with GE switches, I've think I've got an add-on switch you can have for the cost of shipping.
Something that wasn't mentioned: the new Inovelli switches will let you use another smart dimmer on other locations if you want. I can't imagine why you would (It's probably more expensive and an add-on would also give you dimming, but I guess with Inovelli you'd get to make use of the LED bar at the other locations too). They're the only ones I'm aware of that work like this--they can actually work in any of the above configurations depending on whether you have a neutral or not (again, there may be something else I'm not aware of). You can get the switches now, but you'll have to wait probably a couple weeks for the dimmers to finish mass production.
Which model? The ZEN27 and ZEN22 (and presumably its toggle equivalent, but I didn't check) can work with dumb switches but not dumb dimmers. I'm not aware of any of theirs that can.
Yes, as I mentioned, some are capable of working with an existing "dumb" on/off switch. Some require rewiring, some don't. All depends on the exact switch you have, so the product description and manual are essential to consult if this matters for your application.
The GE add-on solution is probably the nicest as you get momentary up/down dim control from both positions. With the zooz ability to work with existing 3-way, it means on-off only from the second position.
Or you could use two of the zooz ZEN22 just as scene controllers, with smart leds, and get touch up/down control from both positions that way.
The HomeSeer ones also support remote dimming (and remote multitaps/scenes). I suspect most do, one of few advantages to using these over dumb switches.
The GE Add-on Switch replicates all of the functions of the switch it is wired to. If that includes dimming, then it also allows dimming. It does NOT show up as a separate device in Hubitat, only the primary will.