I guess that there are "purists" who can't abide the use of any chords other than the Major triad in any song.
I once played with a harmonica player who would have a fit if anyone played what he considered "extra" chords in a tune. The fewer the better was his philosophy. He really got off on songs with one or two chords. It's strange too because he played some mean Chicago Blues on both the harp AND, guitar.
So ya just never know.
I don't personally use Major 7th chords but thats probably because I'm too damn lazy to learn them. I certainly utilize the few dimimished chords I know when the conditions warrant and have even been known to play a 6th or 9th.
I haven't gotten to 13ths though. I guess theres some places I just don't want to go.
BTW, JohnnyBGoode, I take it from your handle that you are at least familiar with Chuck Berry? Check out some of his chording sometime.

troll