Games differ in terms of how to manage the positions of objects, such as having defined zones for different types of gameplay or having related cards and gameplay objects grouped into conventional positions for visibility
In commander, there are tons of spells to be cast from outside of your hand
Lets assume you have a beefy creature on the battlefield, and lets be honest, in green that should be pretty easy
If a card in your hand is already revealed (perhaps because it was revealed to pay a cost of a spell that's still on the stack or due to the effect of a card like Telepathy), you may reveal it again to pay the cost of another spell or ability that requires you to reveal a card from your hand
In July, the One Piece Card Game launched in Japan
Its Psychic can be useful against foes loaded with energy cards, though its Steam Blast attack can only realistically be used a couple of times before it becomes a burden to the trainer's energy needs