Uses crypto.getRandomValues() (Web Crypto API), which pulls entropy from the OS's CSPRNG — the same source used for password generation and TLS. Math.random() is a deterministic PRNG that can exhibit subtle patterns; this cannot. And since Uint32Array holds exactly 2³² values (evenly divisible by 2), there's no modulo bias — Evan and Bradley each have a precisely 50% chance every flip.