[francogt]

> Category theory has virtually zero application to software engineering. > Knowing what a monad is (in the programming sense) has some [practical application]as well.

You’re contradicting yourself. You don’t need to know category theory to use practical abstractions like functors and monads. They are still however category theoretical concepts. If these category theoretical concepts have “some practical application” as you say, then category theory does have application to software engineering.

[umanwizard]

It had application in the sense that it provided inspiration for these concepts, yes. However learning anything else from category theory is irrelevant to understanding and using them.