If you are 5 years old, the way I would explain it is that Bitcoin is like lego pieces, they're fun and easy to play with, you could part with them or trade them in pieces or as a set, could be frustrated at times, they could be cheap or expensive depending on brands or if they're counterfeit, and some could be worth a fortune, for example some of Harry Potter's legos are in the thousands of dollars now even though they were less than $100 a few years ago.
Explain Like I am Five (ELI5) is just an expression meaning that I have no knowledge in that field so keep the explanation simple. it is not literary.
also your way is interesting but wrong in my opinion because it is promoting bitcoin as something like a collectible instead of what it really is which is a currency and instead of focusing on the value of it and promising growth, you should always focus on utilities of bitcoin as a currency.