Since TA recently got an update (
TrueAchievements) which allows you to add games you haven't started to your collection, and I hope the feature will come to TT sooner or later, is there any point to this anymore? This whole thing exists because the only way to add games to your collection in the past was to pop an achievement, but that is no longer the case- and while adding to your collection doesn't change your completion percentage, the feature is still in development and an adaptation to show percentages with/without all games included would make these old fashioned 'dives' redundant.
That being said, I want to support this thread, in new form or old the idea is still an alternative motivation achievement hunting which is a good thing.