I'm not sure if this is supposed to be sarcastic, but taking it at face value, mathematics are the underpinning of both computer hardware and computer science. Since we are talking about more abstract mathematics, it is what gave us the lambda calculus, complexity analysis of algorithms, type theory, relational algebra, distributed systems.
more pragmatically, libraries like redux, react are heavily influenced by concepts from functional programming, rust has novel concepts from type theory, data engineering in the cloud age leverages a lot of algebraic concepts to achieve massive data throughput. We have parser combinators, lambdas, stronger typing, map and flatmap in most languages these days. These all come directly from mathematics.
Oh, I thought your point was that mathematics wasn't bringing anything to computers. As far as I understand it, category theory is more about finding commonalities across mathematical fields (or indeed, scientific / engineering fields), more so than solving more concrete problems.
What does that give you? For me, I think it gives me an easier way to see common abstractions across different problems I work on.
I am at the beginning of my CT journey itself, but a layman's understanding of monads, functors and applicatives gets me really far writing pretty much the same code when i do bare-metal embedded or frontend javascript. The point is not that I couldn't write bare-metal code or frontend code without, is that I am much quicker seeing "my javascript promises are like a monad" and "my coroutines are like a monad" and being able to shrink my cognitive load.
>Functional programming concepts don't require learning category theory
This is such a reductionist world-view. Programming concepts don't require you to learn the theory of computation either, but having a theoretical/abstract grounding for what computation is disconnected from any particular programming language/model of computation helps. A lot.
>Type theory isn't category theory
It depends on what you mean by "isn't".
There is a 1:1 correspondence between type theory and category theory constructs.
more pragmatically, libraries like redux, react are heavily influenced by concepts from functional programming, rust has novel concepts from type theory, data engineering in the cloud age leverages a lot of algebraic concepts to achieve massive data throughput. We have parser combinators, lambdas, stronger typing, map and flatmap in most languages these days. These all come directly from mathematics.