>>314835061The decisions really don't have the same impact when everyone is playing the same deck and using the same strategies. Most of the time the options available to a deck are really, really repetitive and it's really obvious what moves each player is going to make in a given situation based on the deck their playing. Hense the term "flowchart".
When you're playing an out there deck that requires you to out think your opponents, your decisions/small mistakes can make or break you. It's also more fun for your opponent, since they seriously have to think outside of the box to get around your obscure strategies/locks.
Variety is fun because it encourages everyone to play their best to survive and use genuine ingenuity to win.