When someone cracks a game, the end result of their work may not be accessible or easily distributable to average users. Their focus is on cracking the game, not necessarily distributing the crack.
Others like FitGirl come along, creating launchers that take care of any dependencies needed for the game, and in general making it painless to run the cracked game. In other words, they repack the cracked game in a more user-friendly packaging.
If you've seen Breaking Bad, there's a similar dynamic there. Walter may be the one making the product, but he can't distribute it alone - he needs someone to make it widely accessible, if he wants people to actually use his product.
To add to this: I consider myself relatively tech savvy for somebody who is not “a coder“ or similar. That being said, whenever I am interested in a project or something for my computer and I am directed to a GitHub repo, I immediately start calculating how badly I want to do the thing against the steps that are being given to me. If somebody has a stable/relatively easy to run package (like Dolphin), I am far more likely to move forward.
Sorta this but more so the crackers release essentially a bunch of files and folders that runs the game, someone like fitgirl can take a bunch of the files and rrpack them in a smaller, compressed format. This quickly became popular for people with bad connection, as download size is small; and also for archivalists, who don't need to install/unpack the game, just want to keep it as efficiently as possible