While I don't use Kodi, I'll download videos like the ones from WWDC so I can play them back as many times as I want without worrying about the plays counting towards my bandwidth cap. In my case, I've added them to iTunes (and Plex).

If my PS3 didn't have a Twitch app, I'd probably use Plex to stream it.

On my Apple TV, I regularly use the YouTube and Netflix apps, I occasionally use the Vimeo app all legal content. On my PS3 I have CinemaNow for those digital Ultraviolet copies of films. So, there's a lot of legal content. Granted, I'm sure a lot of illegal content is there too.