1. Such bad examples :( Tuples are data types you have to destruct, in every language. Somebody please show me a language where this doesn't require a tuple-to-function-argument translation:

  sayHi name age = "Hi I'm " ++ name ++ " and I'm " ++ show age
  people = [("Alice", 70), ("Bob", 30), ("Charlotte", 40)]
  -- ERROR: sayHi is String -> Int -> String, a person is (String, Int)
  conversation = intercalate "\n" (map sayHi people)

In python you have `*people` to destruct the tuple into separate arguments, or pattern matching. In C-languages you have structs you have to destruct.

2. And performance, you'd think a slow-down affecting every single function call would be high-up on the optimization wish list, right? That's why it's implemented in basically every compiler, including non-fp compilers. Here's GHC authors in 2004 declaring that obviously the optimization is in "any decent compiler". https://simonmar.github.io/bib/papers/eval-apply.pdf

3. Type errors, the only place where currying is actually bad, is not even mentioned directly. Accidentally passing a different number of arguments compared to what you expected will result in a compiler error.

Some very powerful and generic languages will happily support lots of weird code you throw at them instead of erroring out. Others will errors out on things you'd expect them to handle just fine.

Here's Haskell supporting something most people would never want to use, giving it a proper type, and causing a confusing type error in any surrounding code when you leave out a parentheis around `+`:

  foldl (+) 0 [1,2,3] :: Num a => a
  foldl + 0 [1,2,3]
    :: (Foldable t, Num a1, Num ((b -> a2 -> b) -> b -> t a2 -> b),
        Num ([a1] -> (b -> a2 -> b) -> b -> t a2 -> b)) =>
       (b -> a2 -> b) -> b -> t a2 -> b

Is it bad that it has figured out that you (apparently) wanted to add things of type `(b -> a2 -> b) -> b -> t a2 -> b` as if they were numbers, and done what you told it to do? Drop it into any gpt of choice and it'll find the mistake for you right away.