That's totally fine, if you want to work on the sun tracking app in your free time and release it, I encourage it. But there's a lot of weird obsessive niches and I don't think you're going to make all of them, so the people who want weird things to exist should probably fund their obsessive niches. Of course, if you aren't interested in that niche, you shouldn't feel any obligation to use it or pay for it.

as I mentioned in my initial comment, I believe that a great many products are priced wrongly compared to the market. There may be some where it makes sense to go after power users (say, a train simulator game). I believe many more are common things most people will end up wanting at some point, just once or twice a year for a few seconds.