Lots of stable stuff in Japan is (or until recently was as at least some omve to go or java) ruby. It's not that it's horrible per se, but it's not going to be the most performant in some situations. I worked in grails in the past (the jvm version using groovy unsteady of ruby) and it's not the worst.

As someone with his own preferences, I would never implement something in a language no one else knew, at least without leading courses on it first and confirming ability. Bus-factor 1 is no good.