I think it's a few things, but the two that seem most apparent are (1) that not that many people know about them, and (2) that they feel like overengineering, t

I think it's a few things, but the two that seem most apparent are (1) that not that many people know about them, and (2) that they feel like overengineering, too much work, or just too hard when you can just write the code the normal way. For me, I learned about state machines during my CS degree. They seemed like a neat curiosity, and we drew out our DFA diagrams and whatever, and then I mostly forgot about them. My classes never tied that theoretical knowledge to actual code or real-life examples of when something like a state machine would be useful. If anything, a lot of the examples made them seem like a crappier way to hand-make regular expression, and that made them seem pretty unappealing. I definitely understand the overengineering complaint, because the code comes out more verbose, takes more thinking to write and read, and forces you to handle all the edge cases that you might normally ignore because "they'll never happen". I still have some resistance to reaching for a state machine, I definitely don't use them for everything. They've been very useful for a couple recent problems though: Building a "preset manager" for a screen recorder app. You can have a preset selected, or not. A preset auto-populates the choices for screen, resolution, and mic. If someone changes one of those preset values, or you pull the plug on the mic that's selected, the UI needs to clearly indicate you're not matched with the preset anymore. There were a looooot of fiddly edge cases here and a state machine was a huge help in keeping it tidy, and ensuring that it actually works all the time. I tried to do it without a state machine at first but it got very hard to be sure all the pieces were doing the right thing. Trial expiration and license management. The app can be in trial, expired, or licensed. Simple enough! But there are other situations, like the license on disk is corrupt, or the trial data is corrupt. The state machine was a big help in making sure I thought through every transition that could happen. Also really nice to have a centralized place for this logic, and the machine can dispatch notifications, so other parts of the app can react as needed.