For some reason I get weary when I see cheap Chinese products that connect directly to a DC source. Mostly because of the stories of cheap phone chargers catching fire, or electrocuting users.
I'm also a little weary of cheap Chinese products that connect to my network... I'm always a little worried that they'll be doing something malicious, and I don't have the network know-how to prevent that.
That said, I'm not entirely sure the risk is that much greater with off-brand Chinese products than "American" (designed, programmed and made in China) ones.
Since we can't install firewalls on cheap Wi-Fi IoT devices, it would be interesting to have a Wi-Fi router that handles that for you, isolating every device on the network by default. Just have every device have a web control interface so that you don't have nasty surprises from devices starting to communicate on ports they aren't expected to be operating on. Or just close all outbound ports from devices by default, and just open those that are needed to operate the device. Requests to communicate on closed ports could trigger a message to the Wi-Fi admin who could decide what to let open. A smart interface would pre-generate Web searches for the device ID and port trying to open up so you can read up about it.
That's a really cool idea. I've actually considered having a second "guest" network for everything I don't trust my ability to secure, like windows machines and cheap IOT stuff.