Why not?


$ ghci
GHCi, version 6.8.2: http://www.haskell.org/ghc/  :? for help
Loading package base ... linking ... done.
Prelude> let yoba a b = if a < b then 123 else "abc"

<interactive>:1:29:
    No instance for (Num [Char])
      arising from the literal `123' at <interactive>:1:29-31
    Possible fix: add an instance declaration for (Num [Char])
    In the expression: if a < b then 123 else "abc"
    In the definition of `yoba':
        yoba a b = if a < b then 123 else "abc"
Prelude>

>>35
the point of learning a different language is to..
..write code faster and easier, wasting fewer brain resources.

There is no other reason to prefer air transportation to sea one, or Internet to airmail. Haskell compared to Lisp is like sea mail compared to Internet.