I don't follow. Why is 15_000_000 less distracting? What problems unrelated to what we're trying to solve? And what 'default options' are you referring to?
The motivating examples read like nonsense to me. (I don't really speak Rust, but I think I'm reading them correctly? I don't know.) They seem to be saying that 1 + 1,000,000 = 1,000,000; or 1 + 100,000,000 is 16,777,216? With no remark? That's not right even for 32-bit floats.
vec![1.0; 1_000_000_000] is Rust notation for an array that contains 1.0 one billion times. I can understand it's a bit confusing/frustrating if you're unfamiliar with Rust syntax, sorry.
