No, this post is about why a person would want to actively 'hibernate' a wasp over winter. Or, even, thousands of wasps.
To explain this, I've uploaded some pictures that explain the process of hibernating a wasp. And then, a couple of paragraphs on the presumed effects that this has on the ecosystem, particularly in the context of a community with a penchant for wasp larvae. Combined, I hope that this gives a good answer to the question 'Why hibernate?' - In short, what comes around goes around, and if you want wasps next year, well, you'd better hibernate a few this year.
The pictures below explain the hibernation process. (Written explanations pop up when you move the mouse over each picture)
Therefore, by keeping a few nests aside, ensuring that the conditions are conducive to mating and hibernation, and then keeping the hibernating queens in protected conditions throughout the winter months, one ensures that there will be queen wasps who survive until the spring.
In this way, the wasp population (and therefore the forest ecosystem as a whole: As insect predators and flower pollinators, wasps are an essential part of the ecosystem) is maintained, year after year - and people are still able to enjoy the annual harvest of hachi-no-ko!