>Arguably, you'd still have better productivity had you not have to sign-in.

No, that is not arguable for anyone who takes more than a few seconds to think about it. Signing in has nothing to do with authentication, it's about things like "I want to have my own preferences set for showdead/noprocrast/etc. I want to maintain my own lists of favorites." Authentication & security are about making sure others don't access/alter your account or use your property or the like without permission, not about there being infinite resources and everyone being perfectly identical.

>So you are still making a trade-off

Nope.

All the eggs keep being stored in the same place (same computer) either way, but one gives them a deluxe padded package and the other one wraps a random material around each egg.