Functional versus procedural programming is first and foremost a usability problem for developers. The two are interchangeable as far as being Turing complete.
I just spent a week at a Jakolb Nielson's education course on usability. I asked the executive vice-president at the company if they had branched into software development itself, sadly the answer is still no.
Functional programming for the majority of developers is not usable. The article mentions they are are targeting DSL, domain specific languages. Which is fine. For example, Haskell has seems to have found a boutique community in async, MQ world. But, from a usability perspective one is severely limiting ones pool of developers choosing a functional language.
It is fascinating from a human nature perspective that people who think in functional programming are brains are wired differently from the procedural programmer. There is very visceral reaction when either camp is asked to program in the manner they find least usable.
Ultimately I think compilers will get to a development stage where independent of functional programming or procedural programming approaches the same optimized code gets implemented under the hood.
Postgres was originally written in LISP. Ultimately Stonebraker had to make the call that if Postgres was going to get adopted widely, LISP had to go and it was rewritten in C/C++ before being open sourced. As a point of research you all might want to look into the Postgres experience.