> - Skirts credit speculation and arbitrage
reply> - Provides stable pricing in shorter term while accommodating price changes over longer term
How? If you pre-pay $5, your account is credited by $5, and when you make an API request you get charged at whatever the rate is for the model you called at the time you used it. You aren't buying some virtual currency or locking in a specific price.
> - Excites engagement
More accurately, irritates customers by keeping their money without providing any service in return.