Sawzall as a language is quite a bit uglier than the vast majority of general purpose languages. Couple this with the read/emit nature of the language, and it's either useful as a stream processing language, or as a step in a mapreduce chain.

Given how easy other languages are at processing streams, tagging output, etc., and that Sawzall doesn't really have an idea of shared state between "records" (aside from data emitted), it's hard to find things that Sawzall is good at other than mapreduce.