Batteries don't die instantly; you always have a few seconds where voltage is dropping fast and can take emergency action (shut down unnecessary power consumers, flush NVMe) before it's too late. Weak batteries die by having higher internal resistance; by lowering power consumption, you buy yourself time.
I don't know if macOS explicitly does this, but it does try to hibernate whem the battery gets low, and that might be conservative enough to handle all normal cases.
That's why I gave the death at 8%. I imagine the OS controls the hibernation, so it probably won't think that is low enough to trigger hibernation, just a warning. My current laptop will die at 70%, and I have hibernation triggering at 80% just to be safe (it lasts about 10 minutes after being unplugged). From experience, when the power dies it just turns off. The OS has no idea the battery is about to die and when rebooting it requires an fsck (or whatever its called) to get back to normal. So I assume there is data loss.
Also, thanks for all you're doing with Linux on the new macs. I love your blog posts!
I don't know if macOS explicitly does this, but it does try to hibernate whem the battery gets low, and that might be conservative enough to handle all normal cases.