So I would say skill at GPU assembly is in-demand for the elite tier of GPU performance work. Not necessarily writing much of it (though see [1] for an example, this is the kernel of multisplit as used in Nvidia's Onesweep implementation), but definitely in being able to read it so you can understand what the compiled code is actually doing. I'll also cite as evidence of that the incredible work of the engineers on Nanite. They describe writing the core of the microtriangle software renderer in HLSL but analyzing the assembler output to optimize down to the cycle level, as described in their "deep dive into Nanite virtualized geometry" talk (timestamp points to the reference to instruction-level micro-optimization).
[1]: https://github.com/NVIDIA/cccl/blob/2d1fa6bc9235106740d9373c...
[2]: https://www.youtube.com/watch?v=eviSykqSUUw&t=2073s