I'm not a web developer (I develop mostly firmware) so I'm not into all this kind of stuff, but I know it is written in Ruby and runs in a Docker container.
It requires at least 10GB just to be able to install and 20GB just to update once in a while. It takes ages to compile. It's a PITA to update. Plus docker gets stuck with old images (not sure it's the right term) and you'll have to manually clear them.
20GB!! It's a freakin' forum software!!! Some triple A games are around 8GB.
I'm glad someone is asking for alternatives. I think all this overhead is because maybe redistributing a Ruby website it's a PITA and requires a full environment installation. And hell yeah I believe a simple test suite can take 10 minutes to run in that poorly conceived environment.
May be something could be done to the base image.
Or just try running ./launcher cleanup
I've found that I'm not alone: https://meta.discourse.org/search?q=disk%20space
There are entire pages of users complaining about the same or related problems.
At the end of the day, it's (almost) free... so what are we complaining for?
(Disclosure: I did a few small contributions to Discourse a few months ago, but never got more deeply involved than that.)