[eropple]

Nulls exist in Scala. You can return null for an Option[T].

Can't in Kotlin, though.

[kodablah]

When interoperating with other libraries on the JVM you very easily can, which is a very common use case.

[eropple]

You're right. Kotlin provides the null-or-throw operator (!!) to convert a Derp? into a Derp, though.