Hotels seem cheaper in some cities and if you’re solo or with only people who are ok sleeping in one small room with max 2 beds.
As soon as you go to two rooms, airbnb gets more appealing fast.
It’s also great where there are either no hotels, or the only options are motels, if you want somewhere with a kitchen and such.
Good for destination-type getaways where the point is to mostly hang out at the airbnb. Hotels suck for that. Even the nicer suite-type ones mostly do.