I bought into this until I actually tried a 200gm preground pack and didn't miss a thing. The first coffee out of a new bag is a little zinger than the last out of the old one but not by enough to make me miss grinding.
It's not a matter of buying into it or not, it's true. If your taste buds can't detect it, that's no knock on you. Many people can't, and many more don't care.
Then you have those at the other end of the spectrum that invest in products like a Kruve sifter to fine tune the coffee tasting experience.
-Mike