JavaScript

I think it's the take(10) that makes it performant.
I guess things like any() will also short-circuit having to process the entire array through a chain of operators before acting on a subset of the final processed array.
If that makes sense....

But if you are filtering then mapping an array, an iterator won't help. You need to go through every element of the source array (to filter) then every element of the filtered array (to map) anyway. There is no opportunity to short circuit, so an iterator won't help.
Edit: and I bet there is overhead keeping iterators active/alive and context switching as each new iteration gets requested, instead of batch processing an array then moving on to the next batch process.