>That just changes the issue from "how do I get good quality random numbers" to "how do I get a good quality seed". This is completely true, but there is a pro

>That just changes the issue from "how do I get good quality random numbers" to "how do I get a good quality seed". This is completely true, but there is a property that your random numbers have to have that your seed doesn't need in any way: Being uniformly distributed. If you need a random 64 bit number, you want every single bit in that number to have a 50% chance of being 0 or 1. This requirement doesn't exist at all for seed data, the entropy of all your seed data together just needs to be large enough for it to be computationally infeasible to calculate it from the outside. I would say that is a pretty big difference. Also, if you just need uniformly distributed random IDs but those IDs aren't secret and don't need to be unpredictable, you don't even need a seed. Or at least, you can just use a constant as a seed. No interaction with the outside world needed at all.