Resurrecting this thread as I am experiencing the same message when I open my Triodos bank app. I have used the app for around 3 weeks since installation with no error message until today.
The message informs me that "This app won't work properly unless you allow Google Play services' request to access the telephone"
From what I can tell, the app seems to be working despite the error message.
As I have the app only on my tablet, with no SIM, I am wondering what it will try and do if I allow this permission anyway. I guess I will have to experiment when and if it becomes necessary.