At present when using HomeKit and Lutron Caseta for lighting - switches and dimmers are separated and do not appear together. There is one “light” icon for Lutron dimmers (as well as hue bulbs) and another “plug” icon for Lutron switches. They really should all be in one place in the homebar.
Older Lutron systems ( spacer) which is controllable by Simple Control) is not accommodated in the homebar at all. It would be nice if all lighting could be in one place.