Sitting at low voltage at room temp there is still a measurable self discharge long term. When you put them in frig at 38 - 40F, it is no longer measurable. Details have been on RC Groups. This is partly the reason bigger lipo companies use refrigerated storage.
I don't do this for week to week storage, but for anything that will be months or more. My life is pretty much on hold until years end - I'm working 2 full time jobs and a part time job (long story) so I have no time for anything, much less things rc. All my lipos are in frig - checked all voltages 3 months ago when my job(s) situation changed and they read the same now as they did then, I checked them 2 weeks ago.
Freezer is going to far, you don't want to get the media that cold.