Was ist result und warum bevorzugt FP diesen Stil?

const users = [
  { name: "Alice", age: 30, role: "admin" },
  { name: "Bob", age: 25, role: "user" },
  { name: "Charlie", age: 35, role: "admin" },
  { name: "Diana", age: 28, role: "user" },
] as const;

const result = users
  .filter(u => u.role === "admin")
  .map(u => ({ ...u, name: u.name.toUpperCase() }))
  .sort((a, b) => a.age - b.age);