Currying. It’s one of the stalwarts of functional programming.

Is Currying something you need to know about to be a developer?

Nope.

Is it handy to know about?

Yes. Think of it as a pattern for your toolbox. It can allow some elegant solutions and less code.

Is it weird and esoteric?

No; there’s a certain ‘shape’ to currying code but once you recognise it, there’s no mystery.