It's perhaps unfortunate, but such a library does indeed become very popular for the very reason that it is open source and free. I haven't used this, but if I ever needed in-browser CSV parsing, I'd use it. Were it not free, I'd find an alternative or roll my own library with the bare minimum functionality needed for my project. Paying for anything related to CSV just doesn't "compute", for lack of a better phrasing.

This applies to things like date pickers and html5 charts as well. While these could be separated into a separate category based on the fact that their markets are oversaturated, the result is the same: why pay when there are perfectly usable options that are free, or can be done in-house on the cheap if necessary?