[batista]

>I guess the mixins and nesting are nice, but who the hell wants to compile their CSS before it goes live.

Everybody. We no longer FTP the CSS into the production server like it's 1998. We also minify (a pre-processing step) and concatenate (a pre-processing step). LESS/SASS is just another preprocessing step.

>Some times it's ok to have to declare #fff more than once...

Yes, if you are working on some small / toy site. Being able to have logical names for colors and change them all at once is very valuable for anything larger.