Exile Long Rest. The ability to draw specific cards, and of any type, is very powerful, and theres no way that the ability to go back up to your starting life total isnt going to be something to aim for either
Air tends to get trapped when you sleeve cards
It first made its way into player hands in the Domniaria expansion in 2018 and made some pretty cool decks that focused on permanents that can sacrifice themselves, allowing the player to get their effect every turn
You don't want to pass your priority just to find out they can't handle the threat
It only appears on four creatures, with nearly the same number preventing it from doing anything
When doing this, you strengthen your already strong characters since you're playing Ruby, potentially creating a very scary board state for your opponent to stare down