My old dumb roomba with naught but bumpers, ultrasonic and IR sensors works just fine. It's my understanding that it doesn't map/remember room layouts at all,

My old dumb roomba with naught but bumpers, ultrasonic and IR sensors works just fine. It's my understanding that it doesn't map/remember room layouts at all, it seems to rely on stochastic bumping around rooms for an hour. When I want it to run in another room, I pick it up and carry it there. I don't understand why robot vacuums need more advanced sensors, let alone internet connection.