1. High risk. Low gain. If you're talking about the DC method, that is strictly prohibited and well... they like to gamble I guess. I think someone did some math on this that showed something like all DPS players would have to do it, otherwise virtually no time is shaved off. Whatever time is lessened (which is minuscule) is absorbed from the first encounter with Ultima Weapon because of his invulnerability at the beginning of the fight. This just leaves the second encounter with UW and Lahabrea. Each of whom cannot be burned down before everyone else loads in... after all the cutscenes.

2. Equally as idiotic or ignorant. These players either don't care or don't know that their retainer can take care of the transaction right there and then. It's crazy too because even if you do put it up for sale, your retainer starts the default price at its vendor selling price. So they are deliberately taking an extra step to even lower the cost.

So yeah. Some loons out there man. Not much else I can say about it.