This is especially important in decks like Infect that often rely on a single large attacker
But if you have tried to play any Rakdos-centric deck in Modern, you know the nightmare that is Sanctifier En-Vec
Gaining Hexproof is also super-relevant, as it turns off direct damage effects, discard effects, and a lot of graveyard hate all in one swoop
When the enchanted creature leaves the battlefield, the Aura with bestow will stop being an Aura and go back to being a creature on the battlefield
Felidar Sovereign Felidar Sovereign requires you to have 40 life at the beginning of your upkeep to win, and hey, thats your starting life in EDH
I'm not sure how big of an impact an extra turn is in Standard besides 'Scroll thief effect' late game