I think I could do this, from my starting point it wouldn't take me very long to do something useful. But it looks like the meat of this project involved corresponding with a city bureaucracy and cleaning up ugly data to get basic info from it. It sounds awful.

So... if a hobby is just something optional you choose to do and don't make a living at, then yes, I could do this as a hobby. But in the sense where hobbies are things you do for recreation - reading, gaming, woodworking, gardening, etc? This would be far less pleasant than any other hobby I have, and the bureaucracy parts would be actively negative.

I'm glad this happened, and I'm glad if people enjoy doing this sort of thing! But I think when we talk about having productive hobbies, it's worth differentiating "tasks you can achieve" from "tasks you can seek out sustainably without hurting your quality of life". I have productive things in both categories, but I'd only describe the second category as hobbies.