Not going to explain monads to you, but I will tell you this.

You don't need to care about any programming concepts, unless you are dealing with a programming language that employs them. You don't need to care about monads, unless you want to understand Haskell or Haskell-like Scala code. You don't need to care about metaclasses, unless you are writing Ruby DSLs. You don't need to care about borrowing, unless you are trying to make Rust compile.

You may want to care about programming concepts that are not immediately relevant to you to get a new perspective. Monads and monad-like things can be found in a lot of places: most iterators and sequences, nullability, futures and promises, etc, etc. Does it make a difference if a thing is a monad or monad-like in a language that doesn't make use of monads? No. Is it cool to know? Might be.