I know someone's going to ask this, so here's my thinking.
Room to Learn
I'm a relatively new and inexperienced developer, and Scrutiny has proven to be a great project to build my skills with. Having my own fork gives me the freedom to experiment and break things without worrying about messing up someone else's project. It's been an incredible learning experience.
Freedom to Experiment
I want to try things that might be too experimental or niche for the original project. Some ideas might work great, others might be terrible, but I'd rather find out in my own fork than potentially damage the reputation of what AnalogJ built.
Unmerged Community Work
When I started this fork, the original maintainer had been MIA and there were good community contributions just sitting there unmerged. I didn't want to wait around indefinitely when people had already done the work.
Not a Competition
I'm not trying to "compete with" or "replace" the original. I have massive respect for what AnalogJ created. I just want to keep exploring and adding features that I find useful.
If you're curious about what the fork adds, check out the project page.