I have an Inovelli RGB Blub with the Inovelli driver.
Everything works fine however I'm curious what use case the "Start Level Change" and "Stop Level Change" could be useful. I've seen the same on other devices.
If you use a button controller, you can set the device to dim up/down when holding a button and stop when you release it. It then functions like a normal dimmer but with a slight to moderate lag depending on device type/protocol. I use it with all of my zigbee lights, but zwave may be too laggy to be useful.
By this I mean; zigbee has much faster response/higher transmission speeds, but the small amount of lag can make it difficult to hit the dimmer level Iโm shooting for without specifying a slower transition time in the driver (which doesnโt work properly in every driver).
The community app (disclaimer: my own) Dimmer Button Controller can also be configured to do this if you use the "dim while pushed/held" option
With all of the above, the most logical way to use this requires your device to send released events (which you'd use to stop the level change) after either a pushed or held event (which you would use to start the level change). It also requires your device, of course, to support these commands. Hubitat-native groups, unfortunately, do not, so you'll either have to resort to individual devices (may get a bit messy/laggy/inconsistent with a lot of them) or not use these commands there (stepping the level up/down on a press/hold isn't terrible).
Basically, it's a feature most dimmable Zigbee devices support as part of their firmware (and many others do something similar--I assume this was their inspiration), and Hubitat found a cool way to expose it for us to use if or how we see fit. I love it.
Agreed. I have a number of Zigbee buttons and use button controller hold events. This lag has been my biggest annoyance, unfortunately only to be worse with the current "hub slowness" issues currently ongoing. I've resorted to Dashboards to better control dimmers lately.
One thing I have noticed is that with the newer Sylvania Smart + rgbws, they dim down to 1% pretty uniformly even with my 9 bulb group (chandelier). The Sengled bulbs turn off which is very aggravating, and the topper is that changing the transition time seems to do nothing. With the Sylvanias, I can make the transition time longer, and they dim more slowly, making it easier to get the level I want.