If her research had applications, it would’ve turned her pure math into applied math, which sounds less cool. But an application in string theory isn’t always considered a “serious” application. String theory was popular in the 80s, as a model to unify quantum physics and relativity, but experiments since then haven’t really confirmed supersymmetry, which is one of it’s key hypothesis. Some still think string theory can be saved and make new versions of it to account for modern discoveries, but they’re very marginal.