Other people have given great reasons, but I will also mention that as someone who lives inside the terminal it’s often faster and easier to open it right there rather than getting a GUI one going. I do still use one for things that are easier to do with a graphical file manager though, no problem having both
To be fair this is a terminal file manager… only a certain kind of person will be interested in the first place, and those people are likely to be more inclined to leave a star on GitHub.
Personally I believe the stars were achieved naturally but of course there’s no way to know and it never hurts to be skeptical.