I used to have unofficial HomeKit plugs I purchased on those sites before I knew they were unofficial. I originally got them because they were the only ones I could find in my region before that were advertised to be HomeKit compatible.
While they do work in the Home app (it just warns you that the accessory hasn't been certified) I'm not sure it's worth the risk. It might be better to just run Homebridge and purchase cheaper plugs from established companies. That being said I eventually replaced all of my unofficial HomeKit plugs with official HomeKit certified plugs. (WeMo, Gosund, and Hue plugs)
I couldn't vouch for their quality be it in hardware or software; never found out if they're only rebranded Tuyas. But just the uncertainty alone in the hardware forced me to replace them because I wasn't comfortable with plugs in particular that may turn out to be faulty. I occasionally see negative Amazon reviews for smart plugs from established brands with a picture of a charred smart plug, don't know if the problem is a user fault but in any event I thought if that can happen to them what are the chances this no-name plug won't do the same at a higher certainty?