RealBreakingNate: Typically not
Choosing which deck to insert these powerful EX cards into can be vital, for example, while pairing them with the right supporting Pokemon can go some way to preventing opponents from countering them
When an attack is declared involving an opponent's monster and a monster you control that is a Level 5 or higher Normal Monster, or was Ritual Summoned using a Normal Monster, or was Fusion, Synchro, or Xyz Summoned using a Normal Monster as material: You can make that monster you control gain ATK equal to that opponent's monster's ATK, until the end of this turn
Yes, you need to attack, but that's hardly a problem when you have access to cards like Whispersilk Cloak that can make it unblockable with ease
Players can also team up against a single, colossally powerful monster in the middle of the cross, banding together to attack and defend against the shared threat
As an aside, I strongly advocate for people to try this more often: next time you feel like you need to buy cards because youve ran out of staples, type up the decklist of a deck you havent played for a while and then feel free to disassemble it