Honestly, I think it's worth bragging about just how much code re-use and modularity one can get out of combining parametric polymorphism with ad-hoc polymorphism (type-classes).
I literally, just this morning, found myself writing some annoying repeated glue-code, and realized I could shorten it up where it mattered by taking the glue and turning it into a type-class.
IMHO, people brag about type-classes too much with respect to the particular type-classes that embody category-theoretic constructions, and not enough about their original application to ad-hoc polymorphic overloading. If I can think of a Task X which I have to do for a variety of somewhat different types in somewhat different ways, but which is used in a polymorphic way, then I can absolutely make a type-class out of that.
It's like how people think the big secret to object-oriented programming is inheritance, but actual OOP experts tell you to prefer interfaces (which are almost-but-not-quite just like type-classes!) and abstain from building large inheritance hierarchies.
