Here's why:
* Energy is the fuel for attacks: Energy cards represent the energy your Pokémon uses to perform attacks. Without energy, your Pokémon are essentially "out of gas" and cannot perform any actions that require energy, including attacking.
* Attack costs: Every attack in the game has a specific Energy cost. This cost is displayed on the attack's description and dictates the types and quantities of Energy cards needed to activate the attack.
* Exceptions: There are very few exceptions to this rule. Some cards have abilities that can bypass the need for Energy cards, but these are generally very limited and specific.
What to do if you have no energy:
* Attach Energy: Your primary focus should be to attach Energy cards to your Pokémon. You can do this using various effects from your Trainer cards, your Pokémon abilities, or even by drawing Energy cards from your deck.
* Use abilities: While you can't attack, you can still use abilities that don't require Energy. These abilities can help you draw cards, heal your Pokémon, or even manipulate the board in your favor.
* Play strategically: This situation can be tricky, but it forces you to think strategically. You may need to use defensive Pokémon or abilities to protect yourself while you try to acquire enough Energy to attack.
Remember, a lack of Energy doesn't necessarily mean a loss. By playing strategically and using your available resources, you can still turn the tides of the battle even without a direct attack.