How is it useful?

It is concise to pretend that a SCALAR is the same as a CODE, but they are not. Then the hash is here, but it is processed by those routines over there on the next screen, big hash. So the context that would tell the reader that this convention applies is not near the usage. So the convention must be described in comments, that must be kept in sync with the code yada, yada, badda bing blah ...

You're a ... Why you... You are a ... You, you golfer you!

Have fun with your code.