I'd say that it sounds like you made an informed choice, with proper upfront research on it. That's commendable, even if my fanboying over Erlang would like to steer elsewhere :)

My big problem is with companies that don't do any exploratory work like that. Write a prototype in new language/framework with the explicit idea enforced in project management that it's going to be a throwaway. Do a study through hackathon etc like your team did.

Don't just go on meme-driven development, which covers "CTO read a fancy shmancy content marketing piece in colourful magazine while on the flight"