You might breach local wiring regulations depending on your country if your not careful. This could also stifle sales in the EU region.
By wiring parallel to eg a light fitting or socket, you’re creating an electrical spur. Some countries, the UK and possibly the EU only permit a certain number of spurs on any domestic electrical ring main and similar on a lighting circuit I believe. That max includes all spurs so any internally wired house sockets as well, So you may actually have zero available, and even if you have no spurs, it still limits you to that number of cameras. I’m understand wiring anything but a light, switch or PIR to a lighting circuit is also not permitted and all brand new (not like for like replacement) or outdoor electrics require the use of an electrician. I’m sure an electrician will correct me if I have the rules wrong but I believe that to be the position.
WYZE would need to develop a waterproof power adaptor as TheEggMan mentioned above. Even if you can take a spur legally yourself, which you can’t necessarily in some WYZE markets, you can’t simply cut the plug off a power adaptor and wire in it. It would be illegal, a fire risk and potentially highly dangerous from an electrocution pov due to a lack of ip rating.
Equally, by the same token, any kind of step down transformer built into the camera would make it larger, create heat issues, potential electrical interference and carry the potential for electrocution should the camera short and you investigate the failure. The camera would almost certainly have to be highly IP rated and maybe double insulated to comply with EU standards / make it safe if mains voltage was going straight to the camera. Not a cheap move without the other issues concerning the electrical regulations etc.