I believe it is there to make sure the number of concurrent keyfolders is not limited by when the next write is coming, which is usually "there, it's already here". In fact, memory consumption could be higher with this, as you can end up with many versions of values. It depends on initial value of the khash table and typical growth during freeze I suppose.  I have not looked at the implications for the PULSE model, but it does sound like we'll need to work on that soon to merge this work before 2.0.