It's similar to why I buy Bluray without an HDTV, some bought before I even got my Bluray player. It's like investing in the future. The limited pressing of many releases and existence of download codes gives me added incentive to do this.
I agree. The fact that there are limited pressing that won't be available later on, gives you a reason to buy the vinyl now, even though you won't use it until later... plus the download codes (while I don't really care about them) make it a no brainer for someone who would've paid for a iTunes download anyway