Yeah its true that certain chords work better with certain music. Remember what you said before though, theory can get you in a trap. I think it's more important to look at what part those chords will play in your music, not just their sound. The 11th chord is most often an established Suspension chord, harmonically. When a sus4 is taken in a more melodical sense. A 11th chord is a suspension that will pull you in one direction, and the sus4 will want to pull you in another direction. Depending on where the music wants to go, what note it is replacing, and it's inversion.

The 6/9 works in a different way. They are harmonic chords because of the 6th degree, and sound sort of like 7th chords but that sound is replaced by the 9th. The seventh and 9th chords have the same dissonance tone in them, except one (7th) plays before the root, the other (9th)after. Always a M2 or m2 apart.

I would still keep the thought that those chords work will those types of music, which is correct. But don't excluded them based on that idea.