[noelwelsh]

Functors are not useful for much on their own, so they are difficult to motivate.

The Haskell formulation of applicatives doesn't make much sense outside of languages where currying is idiomatic---which is most languages. In these languages you tend to see the product / semigroupal formulation, and here applicatives become a bit trickier to explain as you need more machinery.

[mrbrowning]

Functors enable the Fix functor and, from there, the whole universe of recursion schemes, so I'm not sure that I agree that they're not useful on their own.

[UncleMeat]

Sure but virtually nobody cares about how to finitize a recursive function when they are trying to learn a new programming paradigm. Recursion seems to work just fine in languages that don't have any of these bells and whistles.

"Hey you can implement Fix" is like saying "now you can program in green" for most readers.

[mrbrowning]

Oh, certainly. My assumption was that the GP meant that functors aren't useful on their own _in general_, rather than in the particular context of someone just getting into the typed functional paradigm. And, of course, recursion does work just fine in other languages, but (and I'm saying this more for posterity than as a retort since I assume you're well aware of this point) recursion schemes offer a layer of abstraction over direct recursion that eliminates the need to manually implement various recursive operations for each of the data structures you have at hand. As with a lot of the higher-level constructs in languages like Haskell, that level of abstraction may not have any practical benefits in most domains, but it's nice to have when it does offer a benefit in a particular domain.