It would be helpful for larger threads for sure. I have my comment order set from newest to oldest, which if fine usually, but is a bit harder if I want to go back to read earlier posts.
To be fair, it already starts to become slow on pages with more than 50 replies. But maybe more importantly, in the page with discussions, the same issue applies. As soon as you want to scroll back to older discussions, it starts loading more and more items and becomes slower and slower.
Not very user friendly, and I say this as a product specialist in IT, just bad practice. Especially if it affects performance this much.
