How common are dozens/hundreds of try-catch blocks in javascript code? Developers have long ago stopped caring about uncaught errors because it doesn't matter in the code they are writing, they catch every error they need to and leave the chips to fall where they may.

In the same vein async.js will be catching all errors passed to done(err, response) and in the case of async.series() and similar calls, will stop the execution of concurrent actions as at the first error that is caught.

Therefore I think its completely valid, because even though our examples are different, to most developers it doesn't even matter.

I think you have a completely valid point, and it's probably a better world where we have proper error propagation and composition, just the reality of the situation is what it is.