It’s a rails app from the early 10’s era think heroku dominance. therefore to run it you’ll need a dozen sidecars for things like redis or elasticsearch and others. it has all the fun ergonomics and bloated memory consumption of that stack as well. the all-in-one go based tools are probably better for a solo homelab style deployment (gitea etc)
Eh, it wasn't about the stack, it was the features over quality track they were taking for a few years there where what features they had were impressive (they really motivated GitHub to get off its butt and do some things) but there were plenty of experience and reliability problems.