yugioh 5ds world championship 2010 passwords for cards Yu-Gi-Oh! Reverse of Arcadia use them wisely Password - Yugipedia

So whats it doing on this list then? Well you see, it has another cost in addition to the mana that you have to pay. And that cost is

The main benefit of sending cards to a card grading service is that the sealed, tamper-proof holder it comes back in will verify the condition of the card and help to protect the card

Lastly, note that "mana cost" was originally called "casting cost" up until the release of the Sixth Edition core set, which brought a number of important rules and terminology changes

A reserve is a minimum price agreed upon by the consignor of the property and the auction house

As long as you have Demonic Tutor, you have your most important card for any given situation