I don''t see why assembly is treated like a special case. I prefer to use assembly, but it is really just another language. If you know a few languages, one will be generally better for certain tasks.

Assembly is good to know if:

1. If you want to use assembly
2. Your HLL of choice does not support some low-level function(unlikely). If so, you are using the wrong language or should look for a language that can be linked with your HLL, before using assembly.

3. Your code requires debuging/optimization at the assembly level. This is rarely the case.

Assembly is bad if:

1. You are doing cross-platform development. Not all processors use the same instruction set. Best to trust the compiler until you are absolutly sure you need to use processor dependant assembly.