Silly? Maybe. Lifesaver? Definitely.
I don't know about you, but I've always thought those car-shopping carts at the grocery store are silly--they're huge and clunky and take up too much space in the aisles, and why would you want your kid to sit in one anyways?
Why? Because I got all the way through the grocery store this weekend with no wanting to get down, no pulling things off shelves, and no tantrums! It was awkward to push and huge but it was woooonderful!