I'm not really a programming language expert, but it seems to me that having an implementation being the spec wouldn't be a good idea. If the Streem implementation has a bug, then the bug becomes the authoritative behavior. Any platform specific quirks would also make it difficult to have defined behavior.
"Yes, you can write more concise code; yes, you have a more advanced type system; yes, you can pattern match. There are hundreds of other reasons that Scala makes a great language. When a language can offer me constructs to write more correct code, I'll always be willing to deal with the learning curve."
I think the point was that these are the things that he thinks are of more value to developers than the other good things that Scala offers.
It is spammy. I split this string using ',', and I count 167 names. That is in no way close to "1 or 2 dozen of the most popular artists" number claimed by the author.