The card can still then be played as a land, as it is exiled after the sorcery has been played
Of course, this means you need a character on board that can initiate the challenge before Maid Marian gets value, but there are 11 4-cost characters that all have decent Strength values, so it isn't hard to get something down the previous turn that can take the Challenge
That certainly merits its inclusion in coinflip decks, but for six mana, you should ideally be able to get value out of both abilities that Edgar, King of Figaro offers
That said, it all depends on your favorite formats and style of play
Constantly casting this card out of the command zone will give you a steady stream of opening attractions, and every time you do he will get a boost in power and toughness
You can also pack your deck with payoffs for sacrificing enchantments or permanents