Competitive Magic: the Gathering is a pressure cooker for decision-making. You have limited time, incomplete information, and an opponent actively trying to exploit your mistakes.
In a tournament round you have 50 minutes for three games. A decision you defer is a decision you make under more pressure, not less.
You never have full information in Magic. You know your hand, your board, and what you've seen of your opponent's deck. Everything else is probability and inference. Learning to act decisively under that uncertainty is the real skill the game teaches.