This is a good read. I am sold on this point. At this moment I am using Difficulty Asc. on a permanent backlog I have had for 2 years now. I don’t know how effective it is in my case in comparison to R desc or PSG desc in reality. Eagerly waiting for one of the two to come along.
Now, one of the issues with difficulty_asc was mentioned that the sorting doesn’t change with time as difficulty only changes when grading cards. Even for very old backlogs, thus sorting stays the same as before