I don't know why you'd think that - if you were us would you prefer to make two trips to answer a call bell, explain what drinks/snacks we have available, then prepare and deliver it on a second trip rather than have it pop through on a screen where we have everything to hand and can get it all done in one trip?
It has certainly been enabled on every single longhaul sector I've done on the aircraft. As I say, the system automatically reports back all the stats to inflight services within seconds of landing.
If it's not turned on on your flight, feel free to ask for the FSM and ask them why
(not that I'm suggesting for a minute you should have to)