The main purpose of the slow cooker is so that you can start dinner in the morning before you go to work, then come home in the afternoon to a wonderful smell of a pot roast, soup or stew waiting for you & the kids to enjoy!
It methodically tames and tenderizes even the toughest low-budget cuts of meat with a slow and moderate slight simmer, bringing out the flavor of the meat & veggies, making it more palatable and easier to chew with that famous "melt-in-your-mouth" taste!
Now if you've forgotten about dinner and remembered it too late, then there's always the pressure cooker to make up for the lost time, still helping you put a nice "slow-cooked-taste" meal on the table in little time!