Charizard cards go for 150, Lugia ones for 149.99 and Umbreons for 142
In general, collectors are looking for near-mint (or even graded) copies of cards as investments, which often leads to a huge gap between the price of played and unplayed copies
Yes, it provides an extra reward for playing his game well (and building around making your opponents sacrifice things), but isnt there enough satisfaction and power to be had with foisting awful choices upon your opponent
Its an awesome threat in decks that require players to sacrifice creatures each turn because this card can grow fast when people are sacrificing creatures left and right
Right now I have it in so that I have something good to return with The Mending of Dominaria, but maybe a better plan is to use Bone Dragon and not The Mending of Dominaria, either just relying on Devious Cover-Up or possibly using Bone Dragon to sculpt your graveyard for Gaeas Blessing, though that sounds like the kind of late-game nonsense that will never actually come up, whereas Gaeas Blessing messing up your Bone Dragon will come up