> Is anyone still writing assembly in the age of LLMs ...
Yes. Its "simplicity" is exactly why we pick and assemble piece by hand - we imagine the leanest way.
LLMs are (not just in Assembly, but especially) very precious as a natural language manual.
> an LLM can easily code it without errors
One day it will probably also be able to have sex, and yet we think we will not pass on the experience - unless, like some kind of coding, it will be a "strictly professional only for money" operation (like in Monty Python's Argument sketch).
Edit: as esteemed emptybits wrote above, rephrasing: it's /the Art of/ Assembly.
> Yes. Its "simplicity" is exactly why we pick and assemble piece by hand - we imagine the leanest way
Professionally, assembly is the last thing I would let an LLM generate for me. That's because if you need to write something in assembly, it's because it's critical: operating system context switch, interrupt handler, that kind of thing. You don't want to be 99% correct, you need that code to be 100% good.
I can imagine some other professional scenarios that I'm less familiar with, where you want to write a tight numeric loop of NEON64 assembly and let the LLM do it, because it's frankly a pain to do by hand, and you can test it to some degree of confidence.