One of the great things about a slow cooker is that they don't burn what is in them unless all of the water in the cooker evaporates and a good lid should prevent that.
That is handy for cooking things like ox tail that require several hours to tenderize. Need to cook something for eight hours? No problem. Just slap it in the slow cooker before you leave for work. Going to be late for work? Again, no problem. Your meal should be fine.