Part of it (but certainly not all of it) is because of all the funny instances hanging around. I'm able to exploit the Semigroup b => (a -> Semigroup b) instance in a WIP version for example. And using (<*>) on the Applicative instance of (-> r) is a favorite of mine.
... To be super ridiculously over-the-top pedantic... That Applicative instance is on ((->) r). If you could actually do type-level sections, that'd be (r ->). But type-level sections are the same as type-level lambdas, and they would break a lot about Haskell's type system so they don't exist.
