Voice Control on Ios, is it really useful?

Hello friends:
Using SIri here in mini orders to my phone.
and hope to extent using my Voice in controlling my Iphone, When i tried Voice control from 2 years, i was not happy, because Voice control was listening to Voice over, but now it is not happening.
I tried VOice control for 3 days, and this is what i found, hope you can coorect me or add a new info:
1- Voice control stop listening after any phone call, is there a solution?
2- I always get the "Voice control is not listening" etc, can i stop these messages?
3- are there better orders Voice control can do instaed of siri?

Waiting your valyable replies.
thanks in advance