Maybe this difference doesn't matter but you can technically play Magic the Gathering by copying the cards or drawing your own. Get out a piece of paper, start drawing the stats on the cards. Play the game.

In other words, you're not paying for the game, your paying to collect cards. I never personally understood it but watched friends, family, and co-workers spent $2k-$5k on cards back in the mid 90s.

That seems different to me in some subtle way from in-game purchases in video games.