[duckpunch]

"Closures in particular are a very powerful tool in async/multi-threaded environments, but in the stateless/sync environment of a web application environment, they collapse down to syntactical sugar, and solve nothing that cannot be solved in other ways."

Closures allow for abstractions that are impossible to achieve without them. Yes, you can always get the same functionality, but you will be forced to deal with a weaker abstraction.

PHP has closures however.