As another poster has already said, there is a time and a place for everything and arrivals and departures in busy, crowded airspace with frequency changes galore and a very busy ATC environment is no time to be practicing, that is how heights are bust and ATC calls are missed.
That is not an opposite point of view to Night Mission's post, is it Centaurus? More a statement of fact in a very general way and not attributable exclusively to the high workload elements of a flight.
Once again, there is a time and a place...