Agreed about tail recursion in Python, promoting recursion as an alternative to loops is contrary to the sprit of Python and "one obvious way to do it".

Monads vs imperative languages is a bit different though, since Haskell-style monads are more than just a way of allowing an imperative style. For example many other features like list comprehensions and parsing is also based on monads in Haskell. However the real value of Haskell-style monads is that it is clear when you don't use them. So it is explicit in the type system which functions have side effects and which don't.