It's a misinterpretation of the slides.
In the slides they said searching the market and putting items for sale is both free and premium
BUT the next slides reveal how exactly that work,
you can't sell or buy items in the market unless you use the new cash currency.
It's labeled as free because:
You get "kupo nuts" from daily login, I imagine 1 kupo nut = you can do 1 purchase/sale in the market every day, for premium it's 2 transactions per day.
Then they introduce an additional currency you can pay real money for which allows you to buy/sell items with no limit at an additional cost
In conclusion:
they walled the entire market function behind a microtransaction (moogle coins) and you get 1 free coin per day (2 if premium)