I’ve used it occasionally. I’m certainly not shy about using it if I need/ want something and it’s always been answered rapidly. Shortly after take off I once had a bad nosebleed on a packed full economy flight in Europe with TAP. The two ladies next to me were glaring at me as if frightened my blood would contaminate them. I pressed the call button for a cold damp cloth and some tissues and the hostess asked me to sit in Business which was almost empty while she looked after me.
It soon stopped and then she said I’d better stay in business in case it happens again and I got the full treatment with meals etc. She even went back to retrieve my carry on and put it above me. Great and kind service.
Cue now people punching their nose to get upgraded;-)