Very few things are truly necessary to know, so I was working from the premise that such studies would be undertaken as a way of rounding out someone's knowledge. The direct practical applications of that knowledge to programming are rare, I agree.

I have taught myself to never say that you need to know X to be a great programmer. You'll note that's not what I said with respect to designing CPUs. When I was a hot-shot kid who fancied himself something special, I used to think and say to people that great programmers needed to know X, Y and Z, which just so happened to be things I enjoyed and knew a lot about. After close to a decade of working with a lot of different programmers, many good and some very great, I've found that there's really no easy one-size-fits-all set of prerequisite knowledge once you get beyond the basics that everyone agrees are important to master. I pride myself on being well-rounded and having an equal mastery of high-level and low-level elements, but I can't honestly say that by itself makes me better than someone who is more exclusively focused on either of the two ends. It's mostly a matter of personal inclination.