Those kinds of projects are valuable not because of any significant chance of having to do something similar professionally, but because doing them gives you a

Those kinds of projects are valuable not because of any significant chance of having to do something similar professionally, but because doing them gives you a fuller and more mature mental model for programming. Doing the larger projects listed will give you deep understanding of the stack (compiler/programming language, operating system, network protocols etc) you are interacting with every day. Especially non-trivial bugs and performance issues tend to test this understanding, and if you go through those kinds of experiences, you will be up for the challenge. (I have personally done a toy HTTP server, small compiler, neural network, etc. and will be forever grateful I did so)