In the same origin model, the app that has the data has the edge.

Silos start out with no data.

That's what makes it safe to install a new app or visit a new domain.

But that means there's a massive cold start problem.

The origin has to convince users to put data into their silo in the first place.

The origin effectively gets carte blanche to do what it wants with the data once it's in there.

That's scary for users, so users have to have clear value before they're willing to do it.

That requires a clear primary use case that works even before the network effect value of the service.

The network effect of many users putting their data in the service can only be a bonus.