Banks an Insurance have just really bad marketing, but fraud-detection (aka ML.."AI"), analytics..it's all really interesting, and if you have a good manager who shields you from the internal-wannabe-politicians you can produce software that you can be really proud of (enough time to test/plan etc).

And hell, Mainframes are such a interesting field no one talks about (but one could learn some really good lessons).

Unfortunately it's hard to find out in interviews if your manager is worth their salt.