Diablo Immortal and Video Game Loot

Maddy, Kirk, and Jason are playing Blizzard's new game Diablo Immortal and wondering... what about this is fun? Is it really all that appealing to keep collecting shiny things and watching our bars go up? From there they start wondering about loot in video games. What is it about items that get players so excited? What makes a good loot system? A bad one? And is Diablo inherently corrupt?