Even most people I know who have written compilers haven't written assemblers; neither have most people I know who have written (real, not toy) programs in asse

Even most people I know who have written compilers haven't written assemblers; neither have most people I know who have written (real, not toy) programs in assembly. The argument isn't that it would be useless, but rather that it's an extremely inefficient use of one's time and money if the goal is higher level development - or even, I'd argue, if one was aiming for a proficiency writing programs in assembly. Again, I'd argue that focusing on being proficient at the level someone is interested in is much, much more useful than focusing on making a lot of different toys at a bunch of different levels and in a bunch of different languages. You are going to learn something either way, but jumping around with a bunch of small projects all over the place probably means that you aren't going to retain much and you're not going to have any particular strength at the end. Conversely, if you focus you're going to retain a lot more, since you can incorporate a lot more of your previous knowledge as you get more knowledge - in fact, if you work on a real project instead of a toy, you're probably going to be seeking out a lot more knowledge on your own as issues come up. In the end you're going to be able to say your proficient in your chosen area, and you'll probably be in a good place to expand to other areas (and you'll have a good sense of where you should expand to).