If memory serves, Cory Doctorow commissioned flashbake, and he wanted it not for backup purposes but as the equivalent of old drafts of books and the like for scholarly research. Git in particular will commit with an empty commit message but is not thrilled about it, and I think there are other VCSes that are more anal about that, thus the need for some text was expressed and "whatever was going on for me while I wrote it" in particular was desired.

So yes, it is completely irrelevant for most purposes to you. I suppose it might be nice to run some sort of semantic analysis that notes that someone writes depressing drippy love poems when it's raining out or something, but I'll be damned if I can figure out why the hell that would be important for me at all. OTOH, flashbake also has a plugin that supports some crude notion of where the commit was written (pretty much gotten from the weather info), which might be more legitimately interesting.