I thought I'd post one more time before I go on vacation. In the meantime, if you're itching for more, make sure to check out my posts on Beckett.com. New posts go up every Monday and Thursday. See you in a week.
Why do baseball cards exist? What I mean is, what's their purpose? I'm familiar with the history of cards and its many twists and turns, but for all the books that are out there, none of them gets to the real meat of the question: Why? And if not 'why', then for whom?
The answer cannot be 'for collectors,' because if cards did not exist, collectors would collect something else. The answer cannot be 'for fans of the game,' because fans of the game have myriad other ways of rooting for their team—the game's marketing arm has made sure of it.
I think I've come upon two answers, one for each side of the question. Baseball cards hold the most meaning for, and therefore exist for… drum roll please… career minor leaguers who've finally been given a cup of coffee. As a collector, it's not every day that you get a card of a guy you've never seen before, and truthfully, it may not register very high on your excitement meter. To you that player is just another common, just another guy between the Hero numbers, there to take up space because there had to be someone on that number. But there they are, obviously excited to be posing for the photo, excited that they're going to be included in a card set, excited just to be there. And to them, the existence of their very own baseball card is the icing on the cake. 
For the career minor leaguer, being on a major league baseball card isn't a summer-camp certificate of participation, it's proof that he made it. It's validation that the effort he put in over the years paid off, and that he mattered, if however briefly, in the grand scheme of things.
That brings up my second answer. If baseball cards exist for the career minor leaguer, the reason they exist is for history. That's their main, existential reason for being: to record history. They're artifacts, footnotes. That they're littered with bad airbrushing, bad photos, jokes and useless trivia only masks their importance to the uninitiated and allows scholars to dismiss them as a quaint American pastiche of Sunday comics, pop art and sentimental pastime; something better suited for sticking between bicycle spokes than for serious study.
The Fantastic Card of the Day
Many notable cards have been dubbed "The Mona Lisa of Baseball Cards." Honus Wagner's T206 comes to mind, as do the Donruss Canseco rookie and the Upper Deck Griffey rookie. Without inflating their importance, you could make the case that without these three cards our hobby would look very different, just as Western Civilization would be slightly off without Da Vinci's masterpiece. But that's where the resemblance ends. Griffey looks too happy and Wagner's background is all one color, so that dooms those two. And you're right, Canseco's smirk does make him kind of look like Da Vinci's muse, but his mustache puts the card more in line with Duchamp's L.H.O.O.Q. than anything else. No, there just aren't any notable cards that can really accurately be called "The Mona Lisa of Baseball Cards."
But if we get past the idea that the card has to be of a 'notable player', a contender pops up. I'm referring, of course, to Tampa Bay Devil Rays Manager Joe Maddon, 2006 Topps #590. The background is spot on, with one side definitely higher than the other. Maddon's sporting unisex-style glasses that brings out the yin and the yang, so chalk up a point to androgyny. Plus, I think you could make a case that he's both smiling and not smiling, so add another point. Really, what would make it perfect would be if Maddon had long hair and wore a robe, but nobody's perfect. This is the closest any card has come to truly doing justice to the title of "The Mona Lisa of Baseball Cards."
By the way, on the back of the card it says that Maddon was a minor league catcher when he played and then spent 31 years in the Angels' organization before getting the chance to manage. Way to make your card count, Joe!
