I have a pretty decent outdoor camera system, because I actually wrote some ONVIF software, and got them for testing.

I will not use an external server. The cameras are in an internal DMZ, and no ports are open. I have a Synology server, recording the video.

But the convenience (and well-written apps) for Ring and Nest cameras is hard to argue with. People don't care about this kind of thing, if they can pull up video of their dog taking a dump in the living room, while they are sitting at a bar with you.