On the one hand, you'll definitely get more value out of your energy-producing creatures than your opponent will, but you really don't want to give your opponent blockers, so it gets cut
Yugi, or rather, the Pharaoh, used Exodia to defeat Seto Kaiba in their very first duel at the beginning of the series
Zoodiac was an incredibly strong deck because of its ability to XYZ summon by only utilizing one monster, which meant that players did not have to worry about having a lengthy combo interrupted by a flurry of handtraps
While it was never actually banned, it received an even higher honor, being restricted in Vintage (without being an artifact creature, because honestly, Slash Panther might get restricted in Vintage, someday)
Seto Kaiba relies on his Blue-Eyes White Dragon or Blue- Eyes Ultimate Dragon, while Yami Yugi relies on Exodia and wins completely by luck
One thing Id like to try to do here is not just point out why cards are good, since most of you are already capable of that