Imagine a Free2Play game with an item shop that offered both purely decorative items, and items which gave you some sort of advantage in game… Which one would you rather buy?
I have the distinct impression that previous discussions on the subject were influenced by the contribution of people who actually wouldn’t buy anything.
This is a very important point. If you do not spend money, your opinion does not count for much. “I want you to pay for the game and for me to get everything I want and for you not to get anything I don’t want you to.”
The excluded middle discussed in the comments is paying for content, the model from Wizard101, DDO, and LotRO whereby you pay to unlock quests and zones. Of course, those games also dabble in cosmetics and “convenience” items, some of the latter trending dangerously into “game advantage.” And then we have League of Legends, which sells content, cosmetics, and convenience with no further gameplay effects and hopefully is rolling in currency.