When I was growing up, these seemed to be ubiquitous and I never liked them. They seemed overcomplicated for the purpose, and created a gross and smelly area under the sink that needed more cleaning.
I haven’t had one in years, as a simple sink mesh does the same job. But I don’t really know how other people are. Are under sink garbage disposals still common, and commonly actually used by people here?
What’s insane about it? You eat food and your waste goes to the sewer. The garbage disposal does the same just without it passing through you. Also they’re only really used for scraps (egg shells, vegetable peels/trimmings, bits from rinsing dishes, etc) it isn’t like you’re dumping a whole plate of spaghetti down your sink. If you don’t have room for composting then the only alternative is throwing that stuff in the trash.