That's certainly the reason I wrote my own static site generator for my website.

I knew I was reinventing the wheel but I also knew the learning results would be immense. I usually work in real-time systems and it was great to have a project to learn how to do offline data-in data-out types of problems. The two types of problems can be very different.

Also it gave me a good excuse to finally actually do something with a functional language.

I'd never recommend my static site generator to the general public though.