without that synergy, theyre probably worse than a tapped dual with subtypes, like the ones from Dominaria United, or duals like the gain lands that do something
Dimir requires plenty of mana to get things going, and this can provide an unblockable body to land encoded spells
Grapeshot and Other Storm Cards Storm is one of the most powerful and heavily-reserved mechanics in the game of Magic
In this case, it all depends on the timing: If I activate Sungold Sentinel, then the activated abilitty goes onto the stack and there's nothing you can do to my coven to stop that
That said, a non-mythic rare needs to get quite a bit of play to get above a buck or two and I dont think this has the goods
However, unlike that card, this ability happens passively without exerting it, meaning you can use it multiple times in a turn