Why encourage a student to climb to the overhead of an airfield that may be busy with other traffic or even have transiting traffic when a much safer option is to select a start point (exit point) away from the airfield that he can fly to and then start the cross country(and nav log) from that point. Its also a waste of fuel and money to go to the overhead.
This is yet another relic from the Tiger Moth days of instructing.
Same as with always teaching to join overhead, it may be the safest student option at an unfamiliar airfield that is busy but that doesnt mean it should be taught as the only way to join an airfield. Noticeably some PPLs also seem to think that they always have to join a GA airfield from the overhead.
Teaching expeditious arrivals and departures should be part of the syllabus