Because that's just what the rock act did, as it put together some B-grade video effects with footage of live concerts where it performed the track, mish-mashed with Lady GaGa's "Poker Face" at its tail-end.
The "Kids" cover itself sounds so extremely similar to the original, it's a bit like regifting the same Christmas present to the person who gave it to you, with much of the same wrapping paper.
"Poker Face," on the other hand, is adorable, especially when Weez frontman Rivers Cuomo does that bridge part when Lady sounds like a little girl speaking French. The growling "mah-mah-mah-mahs" are pretty hilarious too.
Also, Cuomo's red pants are just hypnotic.
Just serves to remind you that pop music is made up of much of the same power chords. It's just what you do with them that matters.