I'm sure this has already been mentioned, but I always assumed that the DVD would come out around Christmas time as that is when sales are highest and most special items like this get released. And if not then I imagine it would be released to help promote a new single or album. It wouldn't make any sense to randomly release this in the Japanese market when she hasn't got any current activities. Of course I could be completely wrong, but at least from a marketing point of view it seems reasonable.