A smart lock would be very useful too, e.g. for granting temporary timed access to cleaners etc. But there's no way I trust any of the smart locks on the market with my home security.
I have some smart scales too. They are pretty great.
It isn't the concept that is the problem. It's the lack of standards and long term support. Non-smart curtains, scales, lights, locks, etc. essentially work forever, whereas I'd give smart versions 10 years tops. And I don't really want to lock my house into 5 different vendors' proprietary systems.