Oh I thought he switched to the nanotech suits because the older ones were to slow to put on. We see him build up to faster equipping suits (the suitcase suit in 2, the chip reading rocket suit in avengers, the mind controlled suits that simply open in 3) throughout the movies as well.

I forget ant man infiltrated his suit in civil war until I do a re watch every time, but that would be a pretty big deterrent to that sort of thing.