[pron]

> Programming with abstract types in Java is a pain, which is why (understandably) Java programmers don't do it.

OK, but I never said Java is ML. The example I provided is not uncommon.

> Interoperability between two memory-safe languages is completely useless to me.

Fair enough, but it's clearly not useless to many people.

> Any price is high when you get nothing in exchange for it.

I think that polyglotism and dynamic capabilities are a good deal, and I think that many others find it at least as useful as complete type safety, but, of course, that depends on your needs and personal preferences.