The real point will be "how does a CSG 7.5 compare to PSA"? Is a CSG 7.5 really a PSA 9? Once the industry is able to compare the grades, this should all settle out. If CSG is known as the toughest grader, that should be OK as the auction prices realized should reflect that.
I have three submissions in process, so I have not experienced it for myself yet. I am hopeful that the combination of the known name CSG within the hobby, the sub-grades, and the AI all help CSG claim a seat next to BGS and PSA. But time will tell. I am confident that more and more collectors will demand subgrades tho.