Join servers on your behalf would be required to do something like "Join the World of Warcraft community server" or "join your guild's Discord server" buttons. Theoretically permanent links could work here, but Discord has made permanent linking harder to do for legitimate reasons, and it wouldn't work for smaller servers.

Email and third-party connections seem questionable. Why should Blizzard need to know my Discord account's email?

Yeah, why is this even mildly infuriating? If anything, it's good to see transparency like this.

It's not saying the program will do any of those things without your input. It's just letting you know that your input in one program is using another programs data.

Doesn't rich presence already cover most of that without needing to handover this amount of perms to a third-party?

And for some reason, some permissions are listed twice. Idk if it's a bug or an attempt by OP to artificially make the list look longer.

On one hand, it could be useful with the likes of WoW to have a better chat app with guild servers and rooms. I think many players are already there. Blizz adapts to what is still hot.

But on the other, one's personal discord account can hold a bit more value than an addon to BattleNet, it may have it's secrets, even in the list of servers you joined, and it probably have friends not interested in that at all. I'd probably create a new acc if I need one for that purpose.

I am surprised Discord didn't do something to sandbox Blizzard's integration. Like creating a user who have access to these and those servers with these permissions. Probably they didn't thought about that, but it could've made integrations more safe and viable.