If you've invested $10,000 dollars in Live Stock and Fish, would you like one dodgy purchase killing your beloved Aquarium? I dont have a QT, but if I had extra funds, and more money invested in larger stocked aquariums, I definitely would.
BTW, QT's only have to be very rudimentary. Heater, Lids, water flow and somewhere to hide (no LR, just some PVC tubing) and your done.