The question is appeal to whom. Large employers want you to learn popular languages so that you're a commodity in a liquid market. But that's not a signal of economic value; it's the reverse. It's saying "I'm entirely replaceable."

What you can predict is that those employers for whom clojure (or any other minority language) is either acceptable or preferred are deciding that they don't want commodity, low-margin employees. It's a signal that they prefer not to buy the mass-market offering, and ought to expect to pay a premium.

What that means is that if your only way of finding jobs is to be one of the mass-market crowd, you're unlikely to find a premium-paying employer because that's not where they're looking.