chandra cards mtg Signature Spellbook: You may sacrifice an artifact or discard a card Chandra, Heart of Fire [Core

Inversely, if youre playing a deck thats likely to frequently wipe the board clean, avoid mana dorks

I suppose thats its biggest advantage

So instead of adding bad ramp they just added more lands instead to make sure you keep hitting land drops, which isn't ideal but better than the alternative

Undead Unleashed functions in less predictable ways

Land Color tag templates(None) Reflecting Pool : Add one mana of any type that a land you control could produce

Since green is the color most known for mana ramp in Magic, it is popular for both monocolor and multicolor decks in Commander because faster access to your mana usually increases your odds of closing out and winning a game quickly