It’s not that professionals don’t make mistakes, and beginners do.
It’s that professionals make idiomatic mistakes.
They make mistakes that make internal sense – mistakes that are still in the right tonality, that are still in the right metric feel, that are still in tune and articulated in the right style to the piece.
A mistake made that conforms to those criteria is still an error – but it’s less obtrusive, and it’s less onerous.
Beginners should certainly seek to make fewer mistakes, but they also must learn to tether themselves to all the musical language that permeates the piece, so that they mistakes they do make are idiomatic ones.