scala.util.Using isn't a replacement for Scala ARM.
The former is a stdlib form of C#'s using or Java's try-with-resources.
The latter is a monad.
The highest use of Scala ARM is to make all your resource APIs return ManagedResources.
open(path) returning a file handle that (cross fingers) must be later closed with
Using, it returns a
If an API returns a
ManagedResource, a user can literally never use it and leak resources.
.foreachin Scala ARM. But if you use
flatMap, then you are in monad territory.