It really depends what modern you're talking about. Most moderns are so abundant in supply that getting a 9.8 should be a matter of searching, supply and patience.
For big books, I would say, "yes" the .2 does make a difference, especially with your example of the Walking Dead #1. It may not make a difference to you, but to the collector out there who wants the "best" representation of a WD #1, they want that 9.8 because IT IS better than a 9.6.
Of course, for you (and even for me) in the case of a WD #1, I'm perfectly fine with owning a 9.6. I'm glad to have the book in any shape!
But if we were talking 5 or so years ago when the book was first starting, why not go for the 9.8, because you can and copies were in relative abundance at the dealer level (relatively speaking).
So all in all, people avoid 9.6 moderns (imo) simply because the 9.8's are out there, and they're readily attainable.