It's not a matter of should so much as can. In some languages (e.g. Haskell), functions are curried-by-default; in others (e.g. Lisps), functions are uncurried-by-default. In each of these, I could (if I wanted) write either version, e.g.

    -- Curried and uncurried add in Haskell:
    curriedAdd :: Int -> Int -> Int
    curriedAdd x y = x + y
    
    uncurriedAdd :: (Int, Int) -> Int
    uncurriedAdd (x, y) = x + y

    ;; Curried and uncurried add in Scheme:
    (define (curried-add x)
      (lambda (y) (+ x y)))
    
    (define (uncurried-add x y)
      (+ x y))

Haskell chooses to make curried the default, but allows you to write uncurried functions if you'd like. Lisp chooses the opposite.