When working for a big agency in South Florida when I was still young, the agent gave great advice "Nobody wants to see a sober faced musician."
Probably good for a thread of it's own but...not quite true imo. Even as a concert goer I don't need or want everyone on stage putting on their "face", especially if the musician has something to say through his/her instrument. The keyboardist is probably the last member that needs the fake smile, gaze into the distance, or worse. Even during their solo moment in the spotlight I rather see them concentrating on their craft and giving it their all. No need for any visual entertainment- that's what the lead singer, guitarist and back-up singers are for.
It's the thing that turned me off from gigging long ago. I get that everyone is an entertainer and certain band situations warrant it, but it's often overdone and comes across as contrived. Let there be visual focus.