I think that's were it comes from: people that briefly worked with Scala in the past. At some point it was true, but nowadays the problem is solved because IDE

I think that's were it comes from: people that briefly worked with Scala in the past. At some point it was true, but nowadays the problem is solved because IDEs will show you were an implicit is used and where it comes from. Without that, it was indeed more difficult - but also not more difficult than Java's reflection or DI (where you had and have even less help).