Never heard of that. So I looked it up and it seems a service completely based on discord? Both for the community and support (I presume) as well as accessing the service itself? There doesn't even seem to be any HTTP API. Weird :)
Yeah, it's a neat idea but it's extremely frustrating to use. A really really basic web frontend would make it so much more usable.
On the upside (for MidJourney), you're seeing a HUGE stream (they are hitting the 1 mil Discord members ceiling) of generated pictures and that kinda grows your appetite and you want to also try more and more prompts..
I think it is still in sort of a testing/early access phase. Discord only access is essentially a way of funneling everybody who wants to try it into their captured marketing venue without having to have one of those "give us your email" placeholder pages (also has a bonus "social" aspect where you're seeing what many of the other people who are using it are creating). The final product will presumably be more tailored and web-driven.
It's also an interesting way of balancing what I assume are high operational costs on the server-end by pawning off some of the hosting of assets onto Discord.