Not sure how Telegram supersedes Discord for the majority of what people are using it for lol.
A: You don't host the Discord server...so it's really not an issue that it uses them
B: It's free...completely
C: It doesn't need any of your real details (just an email address you can access to verify your account)
D: Completely X-Platform (also available from the browser)
E: Posts are editable by the OP
F: Has Voice, Video and Screen-sharing
G: Channels with the ability to set permissions for each
H: Posts can be deleted by you (or a moderator) at any point you want.
I: Thousands (literally) of bots to choose from (or just make your own)
J: Content can be embedded (links, music, videos, GIFs, images, etc etc)
That's just the stuff I could be bothered typing.
If you're using Discord to chat, then having your stuff hidden from "the NSA" (why would you even care about that?) isn't really an issue...
So yeah, not entirely sure what point is being made