This sounds very similar to an Etsy or other online marketplaces. The real value is we are dealing with a DAO meaning there is no overseeing body. Those entities take a percentage of all transactions which cuts into the margins people get. People are also stuck paying either MC/Visa or PayPal a percentage for every transaction. On Steem, we know that does not exist.
There are no direct fees but witnesses currently take 10% of the inflation. That may have to change in the future. A lot depends on the future valuation of STEEM.