The result is an emotional roller coaster of a game that puts you inside the action. I don't believe that the heart of its appeal is the just fact that you're using cards. The fact that it plays so quickly does count for a lot though. After searching for the best way to describe the function of the action deck, I would call it an opportunity bottleneck. In any game, you have rules that delimit what is possible.
Most games end there.
Through the action deck, even the moves that make sense are limited by the cards you hold. Even though these decisions are often very gamey, the agony is real. For example, you have three moving groups, and one good terrain in your hand. The terrain can appear anywhere, but on only one group. Well, three moving groups may be foolish, or just risky, but the game system does create anomolies that I'm willing to ignore because it gives so much else in return.