How so? What matters is the price at the time of transaction, no?
I bought BTC at 200, 400, 800, 1200, 3000, 11,000, and 7,000.
I like BTC wayyy better than USD. If I need to spend 2$ at taco bell, I'll just use my bitcoin.
The currency you're using is USD, since that's how Taco Bell set their prices and it's how you're measuring the value of your bitcoins (via the exchange rate).
I've yet to see any business set their prices in bitcoin. Everyone accepting bitcoin payment is setting their prices in fiat currency (e.g. $2), and accepting an equivalent amount of bitcoin (based on market rates); i.e. treating bitcoin as a payment gateway rather than a currency.
It's the same thing.
This a completely emotional argument, there's no logic behind it, you could also regret spending $2 at Taco Bell instead of on Bitcoin.