@chamomile In my experience the primary reasons often boil down to two cases:
1. The only environment they're familiar with is Debian, and *whoo boy* standard Debian packaging is an *adventure*.
2. The knowledge of the tooling and documentation just simply isn't there.
I should note that Arch users tend to actually write PKGBUILDs for their stuff, and ever since the introduction of COPR by @mirek ten years ago, arbitrary packaging of things as RPMs has been on the rise.