A novice question - how significant is the relative size here. Sure - 4 is smaller than 32, but is that really the biggest concern with a JS library (and modern internet speeds)?
While 4kB may fit well in certain packet sizes, this does not help with HTTP headers that can easily have 100 bytes or more.
Yes, it is.
1) For poorer countries with spotty internet, or mobile only that is slow.
2) For mobile, where data use matters.
3) Ideally with a library this small, it's mostly doing exactly what you need it to and nothing else. So it should be faster for what you're using it for. It's not trying to be all things to all people, and the trade off for that should be giving up long-tail features in exchange for more speed.