Protection from blue (This creature can't be blocked, targeted, dealt damage, enchanted, or equipped by anything blue.) : This creature gains your choice of reach, trample, or haste until end of turn
2/3 Declare blockers- The defending player may choose any number of untapped creatures they control to BLOCK attacking creatures
It feels more aimed at Modern Burn decks splashing white
So there are plenty of moments where you can set it off
Red Bulk Arcbond Flamerush Rider Outpost Siege Alesha, Who Smiles at Death 1 Month: $1-$3 Dragons of Tarkir: $1 or $3-$5+ Daghatar the Adamant Monastery Mentor Battle Brawler From Jund reanimator returning Hornet Queen to midrange returning Courser or Rabblemaster or Monastery Mentor to aggro returning Eidolon or Swiftspear or Battle Brawler, there are a variety of shells in a variety of colors that would be more than happy to pay Aleshas trigger
This white enchantment cant save your creatures from removal like instant-speed flicker, but itll blink one of your creatures or artifacts every single turn