This is considered an effect of an attack, so the deck struggles against decks that utilize Mist Energy (TEF 161) , or any other card that prevents the effects of attacks
There's no news of any errata fixes for Ursula as yet though, so the speculation that this will be a super-rare error card is just that, speculation
What is the pull rate for Moltres ex
Molten Birth A lot of the better coin flip cards share a quality with Molten Birth: They still do something even if you lose the flip
For example, my own Mazirek, Kraul Death PriestMazirek, Kraul Death Priest deck (which I'll be showing off shortly) has several creature-based sacrifice outlets, such as Viscera SeerViscera Seer, Bloodthrone VampireBloodthrone Vampire, Bloodflow ConnoisseurBloodflow Connoisseur, Dimir House GuardDimir House Guard*, and Sadistic HypnotistSadistic Hypnotist