I like to think somebody was carrying a loaf of bread home form the bakers one day and walked over grating , tripped, dropped the bread and stepped on it. This pushed it through the grating and instantly turned it into slices. They said, eureka! and the rest is a multi million dollar history.
It is probably more like: What can I do to make my bread a better/different product to my competitors bread? I know – I will cut it up ready so the customer doesn’t have to, they will love that andy bye mine instead.