This is pretty much what I do. For the longest time I'd be hauling a whole armory. The net result was fun, but didn't result in much training value. Moreover, it made tracking all items a pain -- especially at a place like Cheyenne Mountain where one might typically unload everything to their shooting position.
I think there's an additional factor to the training aspect: what can one legitimately carry in any situation for which one might be hypothetically training? Aside from a few admin items in case of an equipment failure, why carry any more than that?
Counterpoint: one might only be able to get to the range 1x a month, so they need to maximize their actual shooting time, and will focus on dry fire, weapon presentation, etc., at home.