> Why the hell would I need the cloud to control a vacuum cleaner?

One reason I can think of is I'd rather be able to remote control a device by pushing my instructions to the cloud from my phone and having my device pull from said cloud, rather than making the device itself accessible remotely.

Another is settings/data persistence (eg: if I replace the device, etc).

That said, I don't have a smart vacuum and none of my smart devices are devices I want to access when I'm not home, personally, so I'm not "for" cloud-based stuff anyway.