That is the wrong way to look at the problem, since in this example you have no alternative payment method. If you have another inflative currency which lose its value as fast as IT products, you would definitely spend that currency to buy IT products and hold the deflative currency
And this is what will happen, people will spend fiat and hold bitcoin. Even if they ran out of fiat, they could possibly take a loan to spend, since the interest of the loan is much less than the value appreciation of bitcoin, they only need to sell small amount of the coin each year to pay back the loan when exchange price is favorable
Good call, maybe merchants will provide some discount, but that is difficult due to high volatility, a merchant might not have so much freedom in timing