Thank you for the thorough response. After looking carefully at what you wrote I didn't really see a difference between the term self-hosting and home network.
You said you have software that automatically downloads media. The way I see this using movies for instance, if I own the movies and have them on my machine, then I can stream them over my network and have full control. Whereas if I "own" them on Amazon and steam it from there, they can track the viewing experience, push ads, or even remove the content completely. I understand that.. But if I want a NEW movie, I'm back to Amazon to get it in the first place (or Netflix, or Walmart, etc. I get it). I'm fact, personally I've started actually buying disks of the movies/music I like most so that it can't really be taken away and I can enjoy it even without an Internet connection. Am I missing something? Unless of course the media you are downloading is pirated.
I know I'm asking what seems to be a huge question but I'm really only asking for a broad description, sort of an ELI5 thing.