Originally, the significance of this card's existence was in connection with Miracle Fusion , and it was expected that the strategy of drawing fusion monsters by reusing fusion materials excluded by Miracle Fusion would be powerful, but it was expected that the turn this card was activated was another Special Summon
Paradox Pokmon were first introduced in Scarlet and Violet, where, depending on which you version you played, either Ancient or Future Pokmon were brought to the present by a professor and their time machine
There's no single official statement, but the practical consensus is logistical: as release schedules accelerated and print runs ballooned to meet demand, running separate stamping operations on every set became more burden than benefit
You can activate the regeneration ability even if Spiritmonger isn't at risk of being destroyed
It doesnt just remove the threat it traps it on the field with no real impact