It's hard to bring something to a BBQ that people will like that's still simple and quick to throw together. Throwing a few bits to fruit onto a stick is pretty much as simple as it can get. And who doesn't like a rainbow! You can dress up that boring buffet table covered in potato salad and baked beans!
This taps right into that toddler part of the brain where you want to pick up a whole pie and smash your face into it. Taking a big ol' spoon and jamming it into a jar of cake and frosting and having no regard for the mess you're inevitably going to make sounds so childishly satisfying. Where's my big spoon?