I always found MSFS useful for doing everything that would meant I lost my job in the real world. Il-2 was similarly useful too for very low flying!
The diversion thing is a good topic. I've had students struggle (relatively)/faff with a planned landaway to another field, so unplanned diversions, although during which you could expect a little leeway from ATC etc, are well worth trying to do (obviously one of those on board needs to be in the know before departure!).