It's a fine system for pug but people don't want it to become the main system for guild raids. When raiding with a guild there are a number of factors to who you gie loot to. For example you don't want a trail to get the BIS highly warforged trinket that dropped when they killed a boss on a reclear over the main stay raider who wiped on that boss 50 times to get your guild the kill. As long as they don't destroy every non-personal loot system then it's fine. Personal loot is great in pugs.