It goes both ways at the same time really. Players also purchase overpriced items whilst the vendor is standing right next to the marketboards. Such as low level jewelry, low level crafting/gathering equipment, and a few other items. Literally not even 10 seconds away. That has very little to do with service. Does form an easy income out of those who can't be bothered to check up value of items. And to be fair is not something people ought to feel sorry for players for. It's very easy to check what the value of an item is, for how much it sells, etc. It's not as if third party websites are required in this game. Even the FFXIV lodestone has its own item db which states exactly where items can be found.