Currently live in a condo, I think every unit in the building came with one
The biggest advantage I could find is that they are insanely convenient for making French press coffee! French presses are otherwise a pain to clean (since there’s no filter to aggegate the grounds), but having an in-sink disposal means I can just flush the coffee grounds directly into the sink. Besides this though I’m pretty indifferent to them
… which is why I never considered French press “inconvenient”… but from what I’ve heard from other coffee enthusiasts, they all found French press inconvenient precisely because they don’t just pour the grounds down the drain & had to dispose it in the trash bin (and deal with the mess). Maybe I’m ill-informed somewhere, maybe something else… I’m not against just flushing the grounds though.