What if it's a lot more performant? It's of course always a risk to incorporate another language, but sometimes performance is a critical feature, yet you have no time or inclination to write (say) low-level GPU code by hand. Futhark is more of an alternative to CUDA or OpenCL than to high-level languages.

Also, there is the important property that Futhark programs tend to be fairly small, and are semantically close to ordinary functional programming. Thus, even in a worst case situation where the Futhark compiler is abandoned, it is a reasonable task to simply rewrite all the code in another high-level language.