Using purchasing power (or more specifically an artificially constructed and highly manipulated bag of goods measure called the CPI in the USA) is a switch to obscure the rate of inflation, as if it couldn't be measured directly.
But Inflation always has been issuance, not purchasing power. Pretending otherwise isa tactic used by people who engage in inflation to try and obscure its effects (because purchasing power is affected by things like growth in productivity.)
Pretending like it's a measure of the price of goods is a political (not economics) tactic used by governments to obscure it-- because the price of goods are affected by other things--like increases in productivity, lower cost goods from overseas and the like.
Currency issuance is related. Is not the same thing
Economic models so far, however, suggest the reward needs to only be a tenth of POW reward.
So with lower fees, lower inflation, and higher throughput the velocity is more likely to grow significantly than decrease.