Bathroom recessed drain so you have a curbless entry into the shower. Whether you shower in a temp chair or transfer to a bench, it's much easier without a curb or rail to step over. If the whole bathroom is treated like a shower floor, with drains, then it's one smooth move instead of 12 million transfers to get to each step.
Wha!!!!! tub in shower-kids can splash and swim as much as they want! This is a brilliant idea for adults too. Whenever I take a bubble bath I end up wanting to shower off at the end. This way you can just step out of the tub and shower off.---- genius. If I ever build a house it will have this.