Nine times out of ten, popular thing is going to be objectively better than obscure thing, because it's much easier to find people who know, and tools that work with, popular thing. All other things being equal, the person who launches a startup based on Go or JavaScript is going to have an easier time than the person who launches one based on Common Lisp or Haskell -- unless they do all the coding themself.

If you have some objective, measurable reason for choosing obscure thing over popular thing, by all means -- tell us why. But show receipts. Actual numbers and measurements.

Otherwise, it's all vibes.