Cryptography, image/video processing, scientific computation (analysis/physics etc), game dev/graphics, microcontrollers/embedded devices, hardware interfaces,

Cryptography, image/video processing, scientific computation (analysis/physics etc), game dev/graphics, microcontrollers/embedded devices, hardware interfaces, compiler/language development. There are probably at least a dozen more major areas I'm forgetting. I've at least used assembly for 3 of those myself (crypto/hw interfacing/compiler dev). It's maybe niche, as far as the job market/skills go, but when you think about it, a hell of a lot of the stuff on a modern Linux system you might use every day is powered by hand-optimized assembly. If you're even visiting this webpage -- the cryptographic stack your browser uses to negotiate TLS, with almost 100% certainty, relies on deep assembly optimization. JavaScript engines are relentlessly optimized at these levels. Any time you visit a page and render an image, systems like libjpeg-turbo are, in no small part, a piece of the puzzle. Using disk encryption or ipsec, too? Assembly in your kernel. It's everywhere!