Alternating feet requires that each leg's muscle groups work in complete opposite to each other. Your brain has to process doing two different things at the same time.
Hopping is probably closer to whatever the first fish to flop up on land and breath air did.
Whereas many languages make functions first class citizens, via the use of this javascript turns execution contexts into first class citizens as well.
You can build up an object of key value pairs and then proceed as if those were named variables in the code.
Obviously it has its pros and cons, but it’s a powerful tool.