and also why ask KIDS ? why not mature people ? maybe they will at least have second thought on what to choose.
Mature people are more likely to have heard at least a little bit about Bitcoin to know it's probably worth more than $100. And if they didn't know, they'd probably make some level-headed response (e.g. "I'm not sure what Bitcoin is so I'll take $100"), which wouldn't be as entertaining as two ignorant teenage girls.
And as posted above, it might have taken a while for that guy to find anyone choosing $100 over 1bitcoin.
I also heard that they have also heard about bitcoin before, but they don't know anything other than that. However, the introduction of bitcoin is now widespread, and most people already know what the real price is but probably don't know how to use it. However, education is still needed to make people like that realize how valuable bitcoin is today.