Reckon it requires greater skill & judgement to make the climbing 180 and descending 180 turns.....
potaroo: I recon you are spot on. "square" works for setting the fundamentals and the curved approaches are for when judjement is able to be used - totally agree.
In real life i have done many thousands more curved approached and departures than square cornered ones, so a it is am important skill that needs to be learned regardless of what type of flying the student will be doing later.
HD