This is my understanding too, though I have no idea whether you get more isomerization from a 60- or 90-minute boil. As for why you’d use this product, I’ll speak from experience and say it does the job and keeps wort loss due to big bittering charges to a minimum.
I guess some people look down on hop extract but it’s a good product. Unless you’re exclusively using your own homegrown hops, malt, wild yeast, etc, you’re getting help from a pro in some facet or other of the brewing process. Good on you if you actually are doing all that yourself, but personally I feel that I get the best return on my time, money, and effort to use things like extract, pellet hops from Washington, well-modified malts, and lab-grade yeast.
