Many operating systems do somewhat under the hood, but UID/GUIDs instead of IPv6 addresses. You could just as easily use IPv6 addresses for the same thing, but

Many operating systems do somewhat under the hood, but UID/GUIDs instead of IPv6 addresses. You could just as easily use IPv6 addresses for the same thing, but you may introduce privacy leaks or have locally scoped resources leak onto an external IPv6 network. Simply addressing things via IPv6 instead of UIDs is easy. The question I'd have is "then what?" Since presumably doing this has a specific purpose, and it isn't self evidence what that purpose is (e.g. Are you using IP coms for local IPC? Are you using it for diagnostics? Is this meant to solve interoperability? Etc). It is neither a "bad" nor "good" idea. It is a neutral idea that could be used either way.