That number includes all colored lands, utility lands, and multipurpose lands such as the MDFC Lands mentioned above
If you need a specific color of mana, you can resort to these lands and some life
I dont think most decks with access to black would even want this outside of Pox, and this isnt going to move that decks tier level
Since White, Green, and Red are all colors that have access to a plethora of token generation as well as cheap creatures, it makes it even easier to ensure that you're getting the most out of your alliance cards
Buried Alive + Reanimate also does amazing things with Phyrexian Devourer Triskelion and Necrotic Ooze
It makes two Black mana when sacrificing recurring things like Bloodghast and Reassembling Skeleton