It's searchable but information doesn't stay pinned and available. It's meant to be a chatroom style place for gaming and as that it's fine but when you want to build a community for something like a video game or a product, what ends up happening is you end up making a channel for every single announcement etc. Say you have a channel for FAQ? You either lock it so only moderators and admins can use it or you end up with a constantly ballooning channel where everyone can contribute. There's no in-between and because each post isn't really collated the way it would be here or on a forum the information is hard to navigate without search which often only gives a truncated section that you can't even navigate to. There's no context more often than not when you use the search function and it's a very poor substitute for a forum as a result.

I don't think discord is a good substitute for a website and I don't think it's a good substitute for a forum but it's being used as both fairly frequently.