the point is that a service like rapidshare doesn't cost the user any money (and instead, get ads). Running a torrent server is expensive, and require dedicated hardware too. You can't really seed from the webhost after all.
The user can use seedboxes, they're far from being as difficult to use as dedicated hardware. They sometimes have some free tier that I expect would be more than enough for a team like xda-developers (think 5GB). It's true that they wouldn't be able to earn money through this, though.
You can seed from regular webhosts - as long as it's a regular http query to a regular http server, not some temporary http query hidden behind several layers of interstitial ads for the premium account.
