An ability that causes damage to be dealt via poison counters, effectively reducing a player's life total to ten, some tend to view Infect as a sort of boogeyman, while others view it as a cornerstone of agro
Then you make a minimum of two mana with Vivi's ability, use one blue to give Quicksilver Elemental the same effect, and then activate it to gain even more mana
Rite of Harmony adds white to the mana cost to allow you to draw cards off enchantments as well as creatures, gets to be an instant rather than a sorcery, and has an affordable flashback cost
In a deck with black creatures, and especially creatures like Blood Artist, the flip could be very costly to one of your oppokn For the front card, a cheap equipment will do if all you want is to satisfy the flip condition
Vigilance is always good, and a hefty +10 means if you can equip it using another ability or spell (like Inventory Management) to Inkmoth Nexus, you get a free player-kill