Just to clarify, my point was that the construction usage is not niche.
But anyway if you continue along your path of reasoning and discount all use cases one by one you end up with no product at all… or maybe a photo/video player and messaging device. But as proven by the construction and many other use cases the iPad is more than that.
Anyway my previous point was not about those being niche industries but niche use cases as far as iPad users.