You can still rent out a room of your apartment if you are living in it yourself.
The issue is about units that the owners are not residing in themselves.
As long as the host stays out of your way when you need (eg, anytime other than when you need them), it's rather quite nice. It's hard to beat the conversation you have over a glass of wine after dinner. I've made lifelong friends this way.
Sure, no one wants to stay in someone's studio with a wall divider, but thats absurd.
Vacation rental homes have been around long before the internet as well if you need a larger place to stay.