With respect, I think you're still missing my point, which is simply that bias introduces vulnerability. Without a real scenario to analyze, the scale doesn't really factor into the argument. A vulnerability is a vulnerability until proven mitigated.

> a tiny fractional loss in an RNG is not going to make a practical difference

I'm not so sure this is true. I don't think either of us is in a place to say whether this vulnerability has practical applications or not. A 1/65536 bias might seem like nothing important to you. It seems like potentially something to me, in a world where the attacker might control the volume of data generated.