> you can "understand" them quicker in Kotlin, but you can't change how they work or use them to implement a new structure.

I'm not sure that extension methods are a particularly fitting example here.

Scala adds a lot of boilerplate for — in my view — very little gain. Of course, Scala's extension methods are actually a special case for implicit conversions; yet, the Scala we write today in my experience tends to avoid implicit conversions per se.

E.g., I'd rather be explicit about a type conversion when that is what I want to achieve: for instance, I'd rather read `javaListMethod(mySeq.asJava)` than `javaListMethod(mySeq.asJava)`. Thus, I'd rather have a first-class construct for extension methods rather than having to write `implicit class RichSeq(val s: Seq) extends AnyVal { def asJava = ... }`

In this case I do prefer Kotlin.