This is even more retarded than the physX guys trying to tell me my gaming experience wasn't complete until I saw a million chunks of crap flying around a la borderlands 2 when I shot something.
I don't need to smell all the things they're talking about, because they SMELL FUCKING BAD. Nobody wants to smell explosions on the battle field, or a festering bullet wound after two days, or that yummy sewer that untalented dev #241 has you slog through because they can't come up with any other fucking kind of level. (kudos to Spec Ops for NOT making me walk through a fucking sewer!)
In short, this is a bullshit gimmick, it won't sell for shit, and it will quickly die out.