Kids are attracted to dishwashers like moths to a flame. There's all sorts of fun sights, sounds and things to touch all on their level. It makes it an ideal candidate for messy projects where clean up is as easy as closing the door.
Dishwashers are fascinating to kids, not just because interesting things happen inside that mystical appliance, but because it's on their level. It's something to stand up against, hold onto and makes for a rather unique place to stage a craft project or place to let them help you mix things up in the kitchen.
Chrissy over at Parenthacks had been hesitant to let her 4 year old help out in the kitchen. Always wanting to help, she's more of a "wild stirrer" and flour flinger than an aid to any sort of cooking. Her dishwasher door happened to be open and the idea was born. Now she can help out without any extra clean up, all she has to do is shut the door and wash it away with her next load of dishes.
Sure you can create taller stools or learning towers for little one's to help out, but if space is short and there isn't a safe place for your little one to help out up high (or store such an apparatus) then try going low instead.