Lutron's Caséta system supports HomeKit quite well. Smart Dimmers and Switches appear in HomeKit and work correctly. But the exception is Pico Remote, which still doesn't seem to be available for configuration via HomeKit.
Ideally, they would appear as stateless programmable switches, such as the Philips Hue Tap. Pico remotes are quite ideal controls, as they (can be wall-mounted) (https://www.casetawireless.com/documents/041458a.pdf) to look just like the "real" Lutron dimmers.
If you have a Caséta Smart Bridge Pro server and a Homebridge server, you may get this feature through a plugin (which is no longer maintained by homebridge) (https://github.com/smockle/homebridge-lutron-case). But it's kind of silly to do that when the rest of the system already accepts HomeKit directly from Lutron's hub.
Lutron has been (asked about this for years) (https://forums.lutron.com/showthread.php/3855-Pico-Remote-in-HomeKit), but after several rounds of software updates without this support, I would like to request this functionality more visibly.