Remember the PSR 8000 had a great facility to change the style from one rhythm to another. I think they were called Swing styles then, and stored in their own bank. You can still do it, but you have to go into a menu and pick things now. More versatile but not as easy.
PSR740 had a one-button push to do the same thing. Your style was instantly transformed from say a 4/4 to a Swing.
Roland came up with something similar allowing to change a style into one of several genres. Very neat stuff, and useful.