> probably doesn't do a particularly good job

It's not the same as a full vacuum run. But it's god as what they are designed to do. Clean a bit every single day.

All the crumbs that fall down in the kitchen over a day, don't get chance to get stamped into the floor. Noticeable less dust buildup on top of counters. I come home and it's done. Mental load removed.

It's neat. And you can get them from 80 EUR. Even if they only last 5 years, that's 16 EUR per year, but saves you maybe 8h per year. Maybe it's because I live in a relative rich country, but here that is not decadent. People buy cars for 50 000 EUR :3