The only thing counting in favor of discord is the ability to use as many servers as you like with a single account, while you might face forums where links in the posts gets visible only if you register an account. I don't recall seeing any discord server so far that would lock posted content from their users. Tho there are servers that request you to agree on terms and go thru some simple verification to prove that you're a human being and not a bot.

Personally, I'm not a fan of situations where communities suggest you joining their discord in order to get in touch with them or receive help faster, because most of the time it feels like I'm joining a playground full of adults behaving like kids.