The reason why we want ids to be purely random is so we don't have to do the work of coordinating distributed id generation. But if you don't mind coordinating,

The reason why we want ids to be purely random is so we don't have to do the work of coordinating distributed id generation. But if you don't mind coordinating, then none of this matters. Surely if it was a great chore for YouTube to have random-looking int64 ids, they would switch to int128. But they haven't. I'm a big fan of the "works 99.99999999% of the time" mentality, but if anything happens to your PRNGs, you risk countless collisions to slip up by you in production before you realize what happened. It's good to design your identity system in a way that'd catch that, regardless of how unlikely it seems in the abstract. The concept of hierarchical ids is undervalued. You can have a machine give "namespaces" to others, and they can generate locally and check for collisions locally in a very basic way.