The original paper was a joke, as anyone who read it knows, for example the Scala version submitted didn't even implement the same algorithm as the other submissions.
That is not accurate. The performance numbers they reported were the idiomatic implementations. The optimized versions were discussed in a different section.
Except that the "idiomatic" implementations were not idiomatic, and the "optimized" versions were not optimized either. The whole paper was a huge joke.