I also always heard that slides are supposed to be guideposts to a presentation, not the main point of one.
I've increasingly been viewing slides as a means to get people to just look up from their keyboard or phone and stop twittering or chatting for at least a minute or two.
I was too; that's why I said "I think". I've heard that too, but it nearly always seems like the "good bits" get put in the slides while a lot of the other things that the speakers say I could have done without. Of course, the rest of the stuff is often interesting, just not usually nearly as useful.
I've increasingly been viewing slides as a means to get people to just look up from their keyboard or phone and stop twittering or chatting for at least a minute or two.