It's partly culture; Scala makes types that little bit easier to use (e.g. case classes, type inference), so things that you might pass as an untyped Map[String, Object] in other languages, you tend to pass as a case class instead. e.g. using spray in scala, the type system will catch if you misspell a HTTP header, because, as the article complains about, they're represented as types.

(Though of course there is an escape hatch, you can use RawHeader(name, value) if you need to).