No, if you comment on the commits themselves rather than the PR 3rd tabs, they disappeared (at least before this change). The only place they were left is your emails, an hardcoded URL or your feed. This was (is?) bad...
they do disappear in one sense: the link to them sent out in the email telling me about them goes away. And if I have a bunch of collapsed comments, it's annoying as hell to find the right one. This is usually an issue when the developer says something like:
"ok, I fixed that, but what do you think about xyz?"
Now I have to go to the comments and expand 35 of them until I find the right one so I can respond to their question.
It's also sometimes the case that changing a line is not the same as addressing a comment, or maybe it only addresses part of a comment, or maybe they just changed whitespace because now all that code you commented on is inside an if...
