Hbd precludes 30m usd pizzas.
It is worth 1usd in hive, regardless of if hive is a dime, or a dollar.
As long as you only use hbd to purchase things, you don't have to worry about a price spike in hive causing you to transfer those opportunity costs with the purchase.
It also allows free conversions back and forth depending on your assessment of future price rise, or fall.
No need to trust exchanges, nor tether.