Clint Eastwood, speaking about how to act on camera said, "Don't just do something - stand there."
Eddie Murphy told Chris Rock to pace the stage like a stalking cat during his standup routines.
Regarding how we move our body in front of an audience, how are we supposed to know which advice to follow?
My personal take is that although purposeful walking/pacing back-and-forth can work as a gimmick or for short segments of frenetic energy, stillness holds up better with time. It's more natural and less presentational.