Honestly the Buttons themselves aren't of much use if you have the Knob.
I wish I'd started with the commander alone. It already does many things standalone. Many of the feature it offers don't even require buttons.
I purchased 2 buttons, one I put on the back of the steering wheel, programmed to flash when single-pressed and "strobe" (chose only 3 times) then double-pressed. The other just behind the screen, opens the glovebox. Yay.
The Knob is nice but could be better. First, you'd expect the 4 side icons to be actionable as on a touchscreen. But no, they refer to the 4 buttons. I wished the 4 buttons had their own displays, then.
Then, rotating the knob changes the "page", and there's the possibility of presetting different pages for P, R or D.
Most of the features require turning the knob (unless enabling activate upon enter), which isn't immediate to understand at first.
They also added sub-menus capabilities, so you can have a set of 5 functions nested within a button press.
What's really nice is the possibility of having 4 memories for seats, and each seat can have a submenu for easy selection (wish you could have written custom names).
Also, you can have a screen for door opening, nice for passengers.
I really bought it for the stalks, and I discovered that even the turning arrows could have been selected via knob buttons.