From a user perspective, blastr is insurance against finicky or unreliable relays and relay operators. It ensures redundancy of users' data so that even if many relays go down, your notes still exist somewhere and likely somewhere others will find them. Outbox model ensures your notes are findable wherever they are, even if on a single obscure relay. But Outbox does nothing to solve for redundancy of your data, from my understanding. With most users onboarding via mobile app clients using a small number of bootstrap relays, I don't see Outbox as being a magic bullet that instantly decentralizes user data and ensures it's redundancy. Blastr does. Maybe you see it as a crutch, but I see it as an extremely useful tool and if some relay operators don't want to host all that data, then all the more reason to blast it out to more redundant relays. Outbox sounds very useful, but it doesn't solve for some things users need.