That varies by person. While it may or may not interest, I'll say learning how to write or generate parsers is a useful skill that might keep paying off.
I keep running into situations where I'd like to describe data in a high level. BNF grammars often fit those situations, are more readable than regex's, and could make for nice parsers. One must know how to parse, though. :)
Never found much use for any kind of generator, they don't scale once you want good error reporting/handle weird edge cases etc. It's nice to have a descriptive, succinct syntax though; as opposed to having it spread out over a recursive descent parser.
That's because they often weren't designed to handle such things. Imagine a BNF-style generator extended with constructs for error handling and edge cases. We already have to do specifications of such behaviors. We might as well automatically get good code out of them.
I keep running into situations where I'd like to describe data in a high level. BNF grammars often fit those situations, are more readable than regex's, and could make for nice parsers. One must know how to parse, though. :)