Completely agree on this point. I've worked over half a decade with smart home systems, and it's just so much easier (and cheaper!) to integrate well documented, open APIs (and please make them secure, I have nightmares of all the open, unencrypted UDP based alarm systems) that is purely local. This means we would highly recommend these products even tho we made zero money off them, and customers would actually prefer them as well - it's well beyond the time of people naively buying this stuff, and they know that clouds can just "go offline".

What also can't be underestimated is the tinker community. Many people in the smart home business are tinkerers themselfs; create a great product for them and they will inevitably try to use it at their job. But this really isn't only applicable to integrators, really.