Here is a snippet from the white paper:
"STEEM is constantly increasing in supply by 100% per year due to non-SMD incentives. Someone who holds STEEM without converting it to SP is diluted by approximately 0.19% per day. While the rate may appear high, for transactions that take less than 10 days, it is still cheaper than credit card processing fees. Furthermore, the daily token creation is insignificant next to the daily volatility.
Someone who buys Bitcoin or any other cryptocurrency and sells it 10 days later could easilylose3%ormoreduetopricefluctuations. SomeonewhobuysBitcoinandthensells it the same day will usually pay more than 0.4% in market fees alone. In other words, the inflation rate is effectively insignificant during the period of time the typical individual will hold STEEM.
The majority of inflation is actually an accounting artifact rather than true reallocation of wealth. 90% of non-SMD inflation is distributed back to existing holders of STEEM
8 of 44
proportional to the STEEM value of their SP balance, making inflation more of a “split”. Only about 10% of non-SMD inflation redistributes ownership in the network."

Anyone can mine and use the steem to promote the network, but understand that is not how the system runs.