If you think that your 0.02 BTC could get you two pizzas tomorrow, you can still buy the pizza today with BTC, and then use the $20 you saved to buy more BTC.
My point is that the decision to transact using BTC is independent from the the decision to accumulate BTC. If you want to hoard BTC because you think it will keep going up in value, then convert all your USD to BTC right now. And then if you want to buy a pizza so you don't starve to death, buy it using any currency you like, while continuing to invest all your disposable (ie non-pizza) currency into BTC.
My point is that the decision to transact using BTC is independent from the the decision to accumulate BTC. If you want to hoard BTC because you think it will keep going up in value, then convert all your USD to BTC right now. And then if you want to buy a pizza so you don't starve to death, buy it using any currency you like, while continuing to invest all your disposable (ie non-pizza) currency into BTC.