Perhaps they're used to it, but are they really fluent in it? Because I keep seeing otherwise bright developers having to use abstraction upon abstraction to keep from screwing up event driven callbacks.
We're in something of a JS framework boom (or hell, if you wish) right now. These people are developing as if their shit libraries won't exist in 3 years. Hence, the total lack of documentation and ongoing maintenance from so many of them. I've already had to maintain code that used abandoned JS frameworks. I'm a little scared of what's around the corner here...
Underscore, Flux, promises.js, Async, Angular, Node fibers, Step...
How much is all this abstraction costing us, both in terms of computation time and developer time (both writing and debugging)?