There's basically four options when you want to watch a TV show without paying money for it. You can borrow someone's password to a legal streaming service, you can use an illegal streaming service, you can torrent the show and watch it locally on your machine, or you can torrent the show, put it on a private server, and access it from anywhere.

The first two options are the easiest and legally safest, but you don't have total control over what you get. The services might not have every episode, they might have awful compression, they might take the show away while you're watching it, etc.

The latter two options are legally less safe, but you have more control over what you get. If you only watch the shows you download locally (either on the computer it was downloaded to or from a flash drive), there's no reason to set up a server at all. If you want to be able to access your shows remotely, setting up a server offers the benefits of streaming legally (watch it anywhere, let your friends watch it anywhere), with the benefits of illegally downloading (you decide what's available to watch, it's in whatever quality you want, no one can take it away from you, etc.)

For most people, just streaming is the best option. Most people don't actually care about quality that much–have you ever met someone who doesn't skip ads? Who can watch a youtube video with the mouse on screen? Who doesn't mind the blighted notch taking away part of their phone's screen? That's most people. Not to say streaming is that bad for those of us who care about quality, just saying that if animeflix or watchcartoononline offer good enough quality for me, they offer good enough quality for 95% of the pirate population