Well, who would pay for that
2, tap: Choose a color, Add an amount of mana of that color equal to the number of creatures you control of the chosen type
You are never forced to activate mana abilities to pay costs, so if there is a mandatory additional mana cost (such as from Thalia, Guardian of Thraben), you can decline to activate mana abilities to pay for it and hence fail to cast the suspended card, leaving it in exile
Maybe a mix of both
So its not like youre getting them at a cheap benefit as well
Dictate of Kruphix, Dictate of Karametra, or Kami of the Crescent Moon are enough reason for your opponents to keep you in play, but they tend to favor everyone equally and don't put you ahead