this means you can't buy anything wet from a pet store that isn't fallowing every wet item minimum 90 days in the presence of no fish
you have to pass anything wet you buy at a pet store, through a separate running smaller saltwater tank or your purchase of pre qt fish is all for nothing.
those two are great sources, I've met in person Dr. Reef and chatted with him years online and routinely refer to his efforts in showing what cycle bac do in threads.
when you buy pre qt fish you're not getting 100% problem-free, guaranteed not one single cell of an invader present fish
you are buying from people dedicated to applying the best possible prevention science of the day, for you and for charge, saving you all that initial effort. sometimes breakthroughs of disease happen, and I'll bet biosecurity issues on the part of the keeper are a big unstated player in that issue
along with their initial attempts to arrest disease before it gets to you, you must pay to keep disease from hitching right back in with that new sprig of macro added to a refugium plumbed into the greater system, that's a biosecurity breach per Jay's article on it.
you are dedicating to things that maintain the protection that pre quarantined fish provide...complete and total fallow verified at your house for any wet item added from a pet store, wet items: corals, snails, a chunk of live rock, a strand of macro, a cleaner shrimp, wet = you fallow it or you undo all the efforts in one single mistake drop of water transferred.
what comes after buying the pre quarantined fish is the full hard part.
the benefit is: you apply the best fish retention science of the day to gain the highest retention rate.
QT fish worth $ is a big deal, they're providing a hard service. they provide the careful means to process hundreds of fish for the best disease prevention science of the day, if I was in the market for marine fish I would buy them from the sources listed.