I have xiaomi unit and I haven't connected it to an app, so it has no connectivity. It does it's job - cleans house 1st floor.

Is it useful to target specific places to clean? Ok, that is a feature that would be useful but I can live without.

Remotely starting? Fancy feature not sure I need - you can aswell start it when leaving the house. Maybe useful for some people when wanting to cleanup after guests remotely, but then again who knows what's dropped on floor there.

It doesn't. And it isn't like hosting a web-portal is some kinda alien technology that can only be done in the cloud. There's absolutely no reason that a robot vacuum couldn't serve its own web interface.