You can't use Bitcoin to buy food, pay rent, or commute. If people were interested in long term storage, then the USD would be down and Gold would be up, instead of the other way around.
BitPay, among others, has a debit card that pulls from your crypto wallet instead of your bank account, using the current exchange rate. You can use it just like any other debit card.
That's still USD at the end of the day. That just sells it to somebody else who wants to use it as an investment (unless things have changed since I've last looked into it). I'm not saying it wouldn't work, but the lack of people actually accepting it as payment is preventing it from being treated as a currency