People like that have a cleaning service, they don't do their own housework. And ironically, the cleaning service is far better equipped to plant surveillance devices or exfiltrate information than a robot vacuum gadget.

Why not both?

Also I would assume it's a lot more dangerous and expensive to send someone in when you can just put an innocuous robot into a room which has cameras and microphones that can watch + listen 24/7 and auto-recharges when the battery is low (unlike surveillance devices).