The Tesla motors example does not compare to currency.
Prices should not be lower. Bitcoin is divisible down to almost nothing. One can buy a Bitcent today for the price of a Bitcoin during the summer. People can put their value into Bitcoin just as they could before-- the idea that because that value grows people would be scared away is silly.
This argument can be made in favor of silver over Gold-- gold would have to be broken into very small amounts for barter, making it inconvenient, while silver can be traded in whole coins. But it holds no water in the context of a digital e-currency.