Love it. IMHO comments are the best part of HN. I always read the top few comments before clicking the linked URL.
The Tesla story currently on the front page is a great example of this.
But yes, there's plenty of "Didn't read the article, but...".
It's not great, and honestly feels a little like in high school when you didn't actually do the full reading assignment for english class, but it can be hard to keep yourself to high standards.
Allowing a super-short summary might be a good practice here, too. Especially for long articles or videos. On videos, maybe link to transcript or slides, too, so people don't have to dig them up. It's another thing I try to do over there.