Awk is a fun, surprisingly powerful language. Even plain mawk can do a lot, but gawk has debugger support, profiling, namespaces, and even network support. (I wouldn't necessarily go out of my way to use most of those features, but it's possible!)
It's honestly worth giving the mawk and gawk manual a skim just to see what all they can do. I want to read through The AWK Programming Language as well.