Bob Jewett said:A list of about two dozen strokes is available in the two articles:
http://www.sfbilliards.com/articles/2005-10.pdf
http://www.sfbilliards.com/articles/2005-11.pdf
although there are some people who claim there is only one stroke. I think the "stroke slip" is, for most players, an idiotic attempt to fix other flaws in their mechanics by layering on another mistake.
But to answer your question, I think an advantage of either kind of slip is that you might eliminate swerving of the back-hand during the slip. It could, conceivably make your stroke straighter. I think there are better ways to do that.
Thank you Bob. I was beginning to wonder if the board had gone insane.