* Because the domain is so specific, there is little code out there that I can reuse, which means there is more room for crafting abstractions. For the first time, for instance, I was able to put my compiler-writing experience to good use in a commercial project, by developing a DSL to define regulations, and creating an editor that allows domain experts to modify them. This is definitely more interesting than other applications that I have built in the past.
* Because the problem is so concrete and I am close to the users, I get to see their joy when the software does exactly what they need, removing friction and sources of frustration from their daily tasks. I also have their trust to direct the project however I see fit, and I feel like I am being successful at involving them in the software development process, allowing them to understand the trade-offs and to prioritize when there are multiple courses of action.
A while ago I came across this comment [1], talking about the advantages of low-volume / niche software. The thoughts very much resonated with my own experience. Since then, I have been asking myself: how many of us are out there, developing this kind of software? Please share! And feel free to get in touch (email is in my profile), since I would love to exchange experiences ;)
[1] https://news.ycombinator.com/item?id=31024822