It's not about actually flying into a Class D airport, but having been taught about it prior to take your check ride. Heck isn't that stuff on the written? It's been a long, long, long time since I took my private written, but it's gotta at least mention class D airports.
There are lots of things I was taught, but never actually did throughout my training. I mean I've never actually canned an engine, but if I'm in any recip. twin you'd better believe it's gonna be "mixtures prop throttles gear up flaps up identify verify dead foot dead engine let's grab the checklist for this" before the guy next to me can say "####!" Not to say you should rush procedures, but as an example of there's just some stuff you need to know.