(Unlike Haskell,) Scala does not force monadic composition on you at all. You can use Scala as a pure OO language, or for old-skool ML-like FP where you don't use monadic context abstraction. I've done both successfully in production. Indeed I strongly advise against a monadic programming style for programmers with a mainstream programming background (imperative and OO).

In my (considerable) experience of teaching programming, imperative programmers find jumping straight from imperative programmers to a monadic style extremely difficult, the more experienced, the more difficult.