This.

First off, this is anything but Unique. Why? The usual reasons: Sticker Auto, bland Topps design. Of course, Joakim could sign a cantaloupe and I would throw down some bills for it. [By the way, Google Image Search "Hits until porn" game revealed pornography on the first page of images. Beware, kids.]
Also, a button is part of a uniform. Why completely remove the button from the jersey and make them two different cards? Thickness, obviously, is one concern. This card would probably be 3x as thick and a regular relic card. The only other reason I can think would be that they never thought to use the buttons until this year, and for some reason, besides the reason that Joakim "Blue Flame" Soria wore them, so they were kept.
On a side note...anyone who was ever a hard-nosed player in high school or American Legion baseball will realize buttons are readily losable when diving. When you think of how many jersey cards are out there, or at least when I do, I think 'why so many'? I figured it's probably because of instances like losing buttons, or ripping the ass out of the back right leg of your uniform stealing second. One of the fiercest competitors I ever had the pleasure of sharing a uniform (not literally, we were teammates for 2-3 years) with would go through 4-5 pairs of pants in a season - which brings me to my next though. So many cards say "game-used/worn Uniform" on them...some say "jersey", and rarely do they ever say "pants". Why not? Jersey implies a top, pants is explanatory, but "uniform", I believe, is intentionally left vague.
Tangent number #18 for this post: New Idea for Topps Unique.
Game used pants zippers. Eh?