Some might argue that if you're using Ruby and are worried about the cost of hashes, you might want to consider switching to another language. There are other concerns about "expensiveness" in Ruby that far outweigh usage of hashes.
That seems like a false dichotomy to me. Clearly I can worry about the cost of hashes and be using Ruby productively and performantly. (Unless I were writing programs whose performance was really dependent on hash performance; I don't use Ruby in those cases.)
Anyway, everything adds up. Even for webapps in Rails or Sinatra, the sheer number of method calls in a single template may contribute significant overhead to the rendering of a page. Which means that shaving a few microseconds off a method call may in fact boost performance measurably. I am hoping this will be the case with named arguments.
