There is in this case, and why Linus did accept the patch in the end. Previous cases less so though which is why Linus is so pissed at this one.
The reason for this new feature is to help fix data loss on users systems - which is a fine line between a bug and a new feature really. There is precedent for this type on thing in RC releases from other filesystems as well. So the issue in this instance is a lot less black and white.
That doesn't excuse previous behaviour though.
What is wrong with a file for this? Sounds more like a local log or debug output that a single thread in a single process would be creating. A file is fine for high volume append only data like this. The only big issue is the format of that data.
What benefit would a database bring here?