personally, I haven't been really impressed with the whole authentication thing and I don't think it's legit (whether if it's SX, GOAT, eBay, etc). unless there are some actual way to authenticate a product's legitimacy is still a lingering open discussion. so-called authenticators rely on imperfections, quality, etc... which is not really accurate at all and basically based on one's authenticators opinion which is still flawed. an obvious fake is easy to spot but high-grade fake is difficult even for authenticators to identify. some legit products are even mistake for fakes. knock-offs have come a long way and is indeed now more difficult to identify especially if the materials and worksmanship is up to par. the only difference being that it is produced in factories that don't pay taxes or employ child labor (which legit companies also do) or go thu channels that make them cheaper and affordable although sometimes sold as much as retail. this does not only limited to sneakers but appliances, electronics, toys, etc...
so if people think that having shoes certified by some person would give them a piece of mind of the cost they paid for a shoe, then go for it. for me, it doesn't make a difference at all and just a waste of time and money. it's not like a guarantee or warranty or an insurance. atleast with insurance, I got to return a product without the headaches of having to plead your case. from my experience, GOAT/SX charge a lot and a pain to deal when you get issues.