The niche situations aren't going to use the built-in rand() anyway because they can write their own or use someone else's that's faster. Even if they end up us

The niche situations aren't going to use the built-in rand() anyway because they can write their own or use someone else's that's faster. Even if they end up using the same algorithm (e.g. a Mersenne Twister) they can still often go faster. Interestingly according to https://bocoup.com/weblog/random-numbers https://bocoup.com/weblog/random-numbers Firefox is just going to use its CSPRNG once the crypto api is ready. (Bug 322529 is still in NEW state, though.)