Exchange rates are important because they indicate a bigger design flaw than the fixed supply: there's no entity with the ability to prop up demand. By contrast, responsible governments with effective tax collecting powers can generally exert a large degree of control over the purchasing power of their currency. The dollar is backed by all taxable economic activity in the United States. Stocks, which often end up worthless after promising starts, are at least backed by assets that can generate future cashflows. Bitcoin is backed by faith.
Even if BTC is better to transact with in every conceivable way, businesses will still need hard currency to pay their taxes, which makes exchange rate and liquidity risk a very real concern if you're trading real assets for BTC.
> a bigger design flaw than the fixed supply: there's no entity with the ability to prop up demand.
That's a strange comment, considering that seems to have been one of the fundamental deliberate choices made in the design of the currency, and is one reason why a lot of Bitcoin enthusiasts are attracted to the currency.
Even if BTC is better to transact with in every conceivable way, businesses will still need hard currency to pay their taxes, which makes exchange rate and liquidity risk a very real concern if you're trading real assets for BTC.