[hibikir]

Yes, monoids and monads are different concepts. Monoids are the easier one

It's not the names that matter, or even necessarily the properties, but the general shape of monads and monoids is one we find ourselves using all over in functional programming. A very large percentage of the Scala standard library is classes with monadic properties, even though Scala does not have a monad type built in.

So it's not that people really need to understand monads to do functionall programming: I think that understanding them is unimportant. The difficulty of the concept is proven by what you mention: Tons and tons of blogposts trying to, and failing to, explain monads.

As far as the utility of monads, just look at actual monads that are very useful everwhere. For instance Option avoids large amounts of null checks, making code easier to write and read. And why is this? Because it's a monad. I can transform any type A into an Option[A], and an Option[A] into an Option[B], by just having a function that transforms A into B, unaware that option exists.

Understanding category theory makes it easier to write good, useful mechanisms that take functions as parameters. But we can use a monad without understanding that it's a monad, and that's fine for most people. It never has to be a thing.