It lets people who want to tinker do it, while keeping people who probably shouldn't tinker from doing it.
It's not available in the Google Play store because the play store rules are really stupid. A lot of apps aren't available there.
Also, it looks like Good Lock is now also available on the Google Play Store, and there it lists Samsung Electronics as the developer [2].
I guess this does make it less sketchy of an app to use, but it still feel wrong to have to do so many weird steps to get a menu option working.
[0] https://en.wikipedia.org/wiki/Good_Lock [1] https://news.samsung.com/global/make-your-galaxy-smartphone-... [2] https://play.google.com/store/apps/details?id=com.samsung.an...