Single point of disaster
I see "cloud" in there and stop reading. There are so many reasons to never connect a home and personal devices to one big corporate owned "cloud."
One good hacker and one good bug can cause widespread physical damage - fires, floods, appliance damage, burglary assistance, stalking, etc.
It's a single point of failure when the corporation has a problem.
It's a single point of obsolescence when the corporation decides that you're not worth bug fixes anymore.
Finally, it's really about collecting personal information and using it to manipulate how you spend money.