Assembly language has several benefits:
- Speed. The fastest programs.
- Space. The smallest programs.
- Capability. You can do impossible things with MASM
- Knowledge. Know assembly language = know your computer
With your MASM knowledge, you can optimize your algorithm better than /O1, /O2, /Ox.
I found this good article from Paul Hsieh Assembly LAB : Human vs Compiler optimization. Please read.