This type of effect is most powerful in mono-black, where you'll have a lot of Swamps to play with, but can also be very effective in simple dual-colored decks
I don't believe either of those rules are in contention for the top spot of "old rules that would still be be sweet to use in oldschoolmtg", but that is a fully different post
Instant Color tag templates(None) Krosan Grip Split second (As long as this spell is on the stack, players can't cast spells or activate abilities that aren't mana abilities.) Destroy target artifact or enchantment
Her first ability is a [Your Turn][Once Per Turn] effect that activates whenever a card is removed from either players life
It would be a bigger deal if it was a vendor that was more towards the top of the market in recent years, like StarCityGames or Card Kingdom
This emotional premium is irrational by traditional valuation standards, but it is remarkably consistent