That is irrelevant as I have explained. What it does is reduce the network effects (merchants accepting and holding Bitcoin thus being nodes in the Metcalf law valuation) within the Bitcoin ecosystem that those holding fiat must buy BTC to attain. If everything they can buy with BTC they can also buy with fiat, then there is no great need to buy BTC with their fiat.
That was precisely my point about why lose 3-5% on double exchange, when one can just buy with their credit card for 0%.
Many people prefer to use BTC rather than credit cards, even though they can use either, because BTC is faster and more convenient for online payments. They buy, wait for the price to increase, then spend when needed. It's that simple. I do not think this 3-5% double exchange loss you are talking is a significant factor in whether or not people choose to use or accept Bitcoin.
More importantly, bitcoin will be (is) finding direct ways to the wallets of people. I suspect some companies that earn bitcoin will offer their employees to be paid in part with bitcoin (rather than loosing the 3-5% on an exchange). Online freelancers of all kinds will increasingly accept to be paid with bitcoin in part or in full. Lots of jobs are going online right now and payment, especially international, is often a headache. There are no reasons why all bitcoins used to buy something must be purchased on an exchange just before. People will be (are) "making" bitcoins directly.