[bunderbunder]

That said, just by eyeballing some graphs at Coinbase it looks to me like the exchange rate was a more volatile back when Microsoft started accepting Bitcoin than it is now. Which isn't to say that they couldn't reasonably decide that it's too volatile, but it does seem odd that they'd do so while the volatility's dropping rather than increasing.

I'm inclined to guess that all the BTC in the news just led them to a more fundamental reconsideration of their bet that it is (or will become) a viable unit of exchange. There are a lot of take-aways you could get from recent events that might lead to that decision, but the most fundamental one is simply that it's become clear that a huge portion of the people controlling Bitcoin's future don't want it to become one.