Microsoft has officially stopped supporting Bitcoin because the currency is unstable.
The reason is that it is so unstable, it can raise or lower prices to the thousands in just one session. Bitcoin exchange rate changes constantly causing Microsoft as well as many other companies have difficulty adjusting rates of products and services in this currency.
Steam also made a similar move when it said it was no longer accepting Bitcoin as a payment method because of high volatility and costs. At that time, because Bitcoin prices soared, transaction costs were close to $ 20 a session and buyers had to bear this cost, pushing the total amount paid by buyers to quite large numbers.