Maybe because it's discoverability is bad. I've been looking for something to control screen brightness because I wanted to give Linux another shot, so this random post was a lucky find.

If I look for this topic on ddg I either find a Ubuntu wiki entry(not really relevant to me on suse with KDE), the arch Wiki which focuses solely on technical details and clis. The first ten articles are clis, a lot of them truly strange ones like writing magic numbers into random system files.

Not a single mention of gddc tho, and the manpage is not a very good advertisement either...

Second Google result for me is the GitHub repository with clear information. You're making a mountain out of a molehill.

I knew about gddccontrol, it's just not what people were looking for when they were asking me about an alternative to Lunar. I obviously gave them any alternative I could find, but all the responses I got were that a simpler easily reachable UI and keyboard shortcuts for changing brightness were what they expected.