Unusual swimming strokes

Why do we stick with the current swimming strokes when there are other interesting strokes. I can think of several that I use and one at least I've seen other people do.

My favourite swimming stroke is what I call rolling breast stroke. It's a very relaxed style. You have to change the direction of roll every so often so you don't get dizzy.
I also like alternating between freestyle and backstroke.
Another nice stroke is back breast stroke. (The name is a vague description but is not very good).
Also I sometimes do side-to-side breast-stroke: the arms and legs do normal breast stroke but left and right are 180 degrees out of sync ie when the left hand is going forward the right is moving back.

The other day I saw someone doing butterfly on their back.

Update: I was just reading the wikipedia article on this. Alternating between freestyle (crawl) and backstroke is called Corkscrew swimming. What I called back breast stroke is possibly related to "inverted breast stroke".