I wouldn't recommend overusing case classes. Scala Tips
mentioned inheritance ambiguities with case classes.
In my little experience case classes help in small matters, in such points, where no extensions are planned (for example, in domain model parts, to avoid equals/hashCode boilderplates). They greatly increase readability in such cases. On the other hand, using them just to save three characters from unnecessary "new" keyword may introduce other concerns. Use them wisely.