These cards shouldn't be counted directly as lands, but three copies of Elvish Mystic can be a fine reason to play, say, sixteen lands instead of seventeen or eighteen in your 40-card Limited deck
This special Trap Card lets you: Place a chessboard Field Spell from your hand, Deck, or Graveyard, to the field, to get you started, AND Special Summons a Level 2 or 7 chessman (pawn or knight) to the Extra Monster Zone, AND Places 1 chessman from your Extra Deck in your Spell & Trap Zone, AND If your opponent goes first, you can activate this Trap from your hand during their Standby Phase
The value of this card is said to increase further considering that this is a rare type of card that is very hard to obtain even amongst card collectors
For an initially cheap cost of 1R, this card generates progressively more noncreature value as it levels up
"Magic: The GatheringFINAL FANTASY Vision Design, Part 2"