- They rarely work very well as a vent.
- They are often installed to low.
- Even when installed to low, a lot of people have to reach up to access them. Not a good thing when handling hot food.
- They're butt ugly.
The entire concept came out of the "space saver" method of kitchen design. In an RV or submarine they're a great idea, in a home they're simply a lazy way of sticking in a microwave without having to think about it.
pretty much this--though it's not just for RVs. A lot of apartments and houses in non-US countries are much smaller on average, and space efficiency is a requirement, not really a design choice.
I think it has been popularized here because of what is mostly necessary over there, and especially with giant furniture stores, which are really "design warehouses" like IKEA that promote that lifestyle, defining that aesthetic.