It’s a fair question. And one I asked myself when I started learning Elixir a few years ago.
But you get paid to solve problems. Not to code.
And that’s a delicate thing you need to understand. Normally if you have a business and you’re uncommitted one way or the other about how a problem is going to be solved, then you have to pick between hiring an untested Java programmer, or someone who knows how to solve your problem with any language.
Providing the language is not too esoteric (and Elixir isn’t) then I would pick the person who has given some thought to how the program would be solved.
Not someone who knows all about list comprehensions (hehe), but falls down on how to process a million records in an hour from Postgresql.