I'll add that ONE of the reasons they're not normally written as dotted sixteenth's is because they're more usually based on triplets or are considered to be a derivative of a 12/8 time sig. The unequal note of the french baroque is closer to a double dotted sixteenth and would never bounce as much as a blues shuffle. The shuffle of the blues is different from the swing of jazz. There's an infinite amount of space between one note and another in which to place a middle beat. Written music is an inexact attempt to record how to play a piece and it is only a beginning point. The amount of the ranges of variation in phrasing and style are almost endless as you will find when you start your own attempts at interpretation. When I went from 20 years of drumming to playing a woodwind with a small ensemble, It took months to get used to how free they were with the time. Even now, on the piano, my teacher struggles to get me to play what she calls "freely and with expression."
I just wanted to be just "a" guy. That's enough of a life.