I am renovating a basement laundry room and I'm wondering what the intended uses for a floor drain are...

For example, previously the washing machine drained into a laundry tub, which drains via 1.5" ABS into the basement floor drain. I've moved the washing machine and now it drains into a proper 2" drain connected to the main sewer line on the other side of the room.

Basically, I'm wondering if the laundry tub draining into the plumbing for the floor drain (under the concrete) is a hack job, or if that's considered "OK". The house was built in 1974 and the drain seems to work fine.

If that's considered OK, then for curiosity's sake, what about a shower, or even a toilet? (Not that I'm planning either, but I'm curious as to the capacity of what I've always considered an "emergency" drain.)