I'll keep this around if I ever need to write a compiler.

I don't know if you're being sarcastic, but a compiler is worth writing as a learning exercise, if not also for fun. Not necessarily a matter of need.

In my last year at uni, I followed a compilers course "for fun". Some people advised against it, because it would be a time-consuming course with little practical value.

At one of my first job interviews, the interviewer said "Why did you waste your time with a compilers course? What good is that for? I don't see any [insert-tech-hype-of-the-day] on your resume!".

So I went to the next job interview I had lined up, and gladly signed up for their compiler developer job opening.

Serendipity?