I don't think that we should take this a good sign from them. They are just cashing it out, and they are right, perfect time to convert it to USD because the price is mooning. That's lots of cash to help whatever cause they want with the millions. They can even buy another sophisticated toys or venture it in an "experiment project" to catch criminals who are using bitcoin to hide their activity.
I also don't think that this will have a impact to the market. The only effect I see is that maybe some of those who have been paid in bitcoin will somewhat re-invest in into the ecosystem. But I wouldn't be surprise if they are not. No need for them to spread the knowledge since Japan has already legalized bitcoin. By this time I assumed everyone is already familiar with it. There's also a lot of questions in my mind regarding the payment system, but I will just keep it myself. You can't really stop admiring Japan though, they are really leading this bitcoin march to the next level.