It's also a question of density; if he's simply saying a lot in very little, or assuming you'll do the menial work like a paper will (offers a theorem, properties and consequences, but proving the theorem is left as an exercise for the reader), then itll have the same property of having to re-read it, or rather, read it very carefully, but still be very valuable.

The difference is in the goal. If its just pedagogical, then you'd want to explain it in three different ways, hoping one will stick; but if its also intended as a reference to review, and discuss, after understanding the general principles (and believing in the theorems), then conciseness is preferable. Three different explanations just makes it more difficult to figure out what you're looking for