Serious answer: Because many developers regard assembly as some sort deep magic only understood by elder gods.
This, of course, comes from some vague (and not entirely correct) understanding of "assembly" running beneath everything else, and thus being fundamental, yet not immediately useful to a large category of developers today. Hence it seems important but archaic. Archaic + difficult = elder knowledge.
I've actually had a few coworkers think I'm some sort of elder god when I find the root cause of subtle bugs that would've either required deep knowledge of the C++ standard, or not-as-deep knowledge of Asm. These are bugs that others have spent many hours staring at the source and stepping through in a debugger without any better idea of why they occur, but are solved in minutes by a glance at the Asm. IMHO if you are working with native code at all, it's a very useful skill to have.
Even though it was a bit of a "sufferance", I enjoy having been full circle somehow. Starting with Java OOP in college, then went lisp maniac [1], then ml/FP. Which were all somehow further away from the machine, in a way. But at the same time lisp model seems a fairly thin layer over raw asm. And you realize that primitives of computing: arithmetic, logic, iterations.. are very similar whatever the language or paradigm. I then learned a bit about continuation, non determinism, compilation and now I'm almost free. A language is mostly an encoding. Most of them speak about the same things but in a different clothing.
Not 100% free, I think I need to finish my compiler training and forth bootstraping before I can claim that.
I can't really suggest others to follow the lisp, ml, prolog road though, so I'll just state what I wrote above.
[1] SICP especially, with its gradual pedagogy. From substitution, to environment, to register machines. You can see the relationships up close.
From my experience most of the hard to trace errors come from uninitialized variables and they are usually valgrindable. It is VM-based so it can cache jumps and other conditions that depend one uninitialized vars via taint analysis.
