@BeAware By looking up the account on bsky.app you prove 2), but not 1).
What do you need to communicate with someone: you make records like follow, like, comment to your PDS. You don't need Bluesky servers for that.
But you also need to read their replies in notifications/threads/timeline and the posts they make in a feed. For that you need an AppView you can pull this data from. Right now only Bluesky runs an AppView.