If you want to see more examples of handwritten Asm then look at the 512b and below categories in the demoscene. Some of those have appeared on HN too:
The second example only proves my point further: It's a demo from the demoscene. Impressive, but pointless outside enthusiast circles. I'm not going to comment on it.
Regarding the first example: Cool! Really interesting and I wish the contractor / employee all the best. Not many people who can do something like this. That said, are we really forcing compsci students to learn ASM for an entire semester, on the off-chance that they'll end up in a leading security role managing major software products? I feel a different curriculum would be more effective (maybe one that teaches how to avoid these bugs in the first place?).
The only real life application of handwritten ASM that I'm aware of, are the initialization routines for most programming language runtimes (GoLang and C++ come to mind) and microcode optimized shaders in game engines.
If you want to see more examples of handwritten Asm then look at the 512b and below categories in the demoscene. Some of those have appeared on HN too:
https://news.ycombinator.com/item?id=7940212