One real world security problem is the "elder account" problem: as the age of an account increases the likelihood increases that it uses an insecure old password and/or that the account owner isn't paying as much attention to the account in the present. Depending on what the account represents age may also imply more "value" in the account. (Including just "sentimentality" value in the case of ransom operations, not just financial value.) Being able to tell from an ID alone that an account is at least X years older than some other ID in the system can be a handy way to find "potentially high value/low security" accounts to focus on to social engineer.

There are certainly mitigations that can be made and not all things are equally valuable as they age. (Plus many public APIs include created/modified timestamps anyway. The information is often easy to discover even when not embedded in an ID.) I don't find it a strong reason to avoid timestamp-based IDs for the threat models of that many things beyond user accounts and other things susceptible for social engineering, but it is something to keep aware of.