Why doesn't grep ignore binary files by default?

Not everything that grep thinks is a binary file, is actually a binary file. e.g. puppet's logs have ansi color coding in them, which makes grep think they're binary. I'd still want to search them if I'm grepping through /var/log though.

grep’s ability to search binary files is also useful when I’m compiling a program and the linker (ld) complains about some function not being found.  I can use a command like

grep function_name /lib/lib*

to find the library which contains it.  (Libraries are binary files.)