Plus it fuels your graveyard and slings deathtouch around
As blue is also the color most associated with card draw, even if the top card of your library isn't a Merfolk, you can reliably ensure castable spells are atop your library through the use of card drawing effects and scrying
Craterhoof Behemoths always been a $25-30+ card, and its a staple and finisher in many formats
The Innistrad: Crimson Vow Set Booster Box contains 30 Innistrad: Crimson Vow Set Boosters and 1 traditional foil Dracula Series box topper card
A lot of blues sacrifice is meant to interact with Zombies or artifacts, but it does have one interesting use case: sacrificial counterspells
11.3 If a Seller withdraws a Lot from sale after the Company has advertised and/or catalogued the Lot for auction but before the Lot has been put on view, the Seller shall pay to the Company the Expenses plus a withdrawal fee equal to 25% plus GST of the higher of: (a) the average of the Estimated Selling Range high and low estimates