Is there a benefit of using floating menus over stream deck triggers? Or is it two ways of doing the same thing?
Floating Menus are much more flexible and can work on all kind of MacroPads - the Stream Deck ones are limited to Elgato devices. Basically Floating Menus are the newer approach but MacroPad support is still a work in progress and was only added recently.
Is the goal to support floating menus and deprecate stream deck once there's feature parity?
not really, but the floating menus will receive new features while the stream deck implementation is kind of complete and probably won't get much new stuff. It will continue to work fine though and I will fix bugs if reported!