While amd64 is better in that it gives more registers for compilers to use, we rarely need to "move on". In fact many programs will work better (more efficient, faster) with 32bit pointers (as many programs would with 16bit integers instead of 32bit ones, where possible ofc). Realistically nobody codes for performance anymore so x86 or amd64 is not much difference (for math stuff, sse(1-4)/avx(1/2) don't care about amd64 vs x86).
Anyway, learning amd64 when knowing x86 is easy as they are mostly the same.
Anyway, learning amd64 when knowing x86 is easy as they are mostly the same.