Twenty or so of my friends of friends use Telegram. None of them use it for mundane things such as chatting. You name the content, you have a channel for it, ergo you have direct download links for it.
But how is this any worse than downloading illegal content through torrents (TPB et al.)?
EDIT: Should have worded this more correctly. I am not a participant in pirating stuff through Telegram, my friends are; I use it for Android stuff (Substratum, custom ROM support, etc.).