I used Futhark in the past. It's probably been 5 years or more, so a lot may have changed since then.

It's absolutely a much lower barrier to entry, especially if you are familiar with functional programming. However, it also leaves a lot of performance on the table, and I found it to be hard or cumbersome to integrate with languages other than Python at the time.

And you're still stuck with CUDA (which is single vendor) or OpenCL (which is a pain to set up on most consumer systems, and has very lackluster driver quality for a lot of vendors). I would have liked that by now support for Vulkan compute or OpenGL compute shaders would have been added, but alas.