I thought if it's z-wave, it'll work

But, that’s not necessarily the case. And if it works, it may not work with something else. I would figure finding a zwave key fob would work with a ST’s compatible door lock.

I don’t think they’ve ever said if it is z wave it does work, but that it can be made to work. Whereas Zigee protocols can be made proprietary.

Remotes aren’t yet fully functional, the issue is that they act as secondary controllers. I know a lot of work has been done though and progress has been made.