A divisible and fungible asset like a currency can never be "too valuable to spend", since by definition you get the value of the amount you spend.
Of course it can. Lots of people here would not sell bitcoins at the current exchange rate because they think it's too low, so why would they spend them for something using the exchange price as reference? Unless they have no fiat currency it would be irrational, because converting fiat to bitcoins has a fee. It's more economical to use the fiat.