You're welcome. I understand that a lot of what I've said is technical jargon and nonsense to the average *.bsky.social user but a lot of it can be simply dumbed down to "the client can choose to ignore it" or "get off Bluesky servers, lol?".
At the risk of sounding like a shill, I would also say that the protocol is much less mature than ActivityPub or Nostr, but the rate of progress that I've seen is pretty rapid (compared to APub at least, Nostr is also a rapidly-developing protocol but its harder for me to track its progress as there's no reliable source for protocol updates that is not on Nostr afaik) and with the active developer community surrounding it I firmly believe that most of these issues will be solved within the next few years at worst. Zeppelin has also progressed on bringing back some of these missing features, as video processing and chat have been introduced to the AppView (albeit proxied through Bluesky's services so it's a moot point).
There's an important distinction to make between AppViews and an APub instance, which is that AppViews handle solely the application portion of the user experience while APub instances typically manage the entirety of the user's experience. As a result, ATproto users can hop between any AppView without any lock-in to a specific AppView provider as their accounts aren't bound to their existence (which means that anyone can switch from using the Bluesky AppView to the Zeppelin AppView with little difficulty (or any other AppView)), while users on the Fediverse cannot easily do the same (applications can authenticate with a Fediverse account to confirm their identity but there are limits to what you can do, such as federating with the identity of that user). They're also not designed to be closed/single-user instances, mainly because the PDS handles the role of user management and platforming users and is where most of that responsibility is placed at. In regards to active usage, enough moderation controversies have happened with Bluesky Social's policies to the point that a small (at this moment) market has opened for a Bluesky with truly user-controllable moderation, and that Zeppelin will be one of the main products to serve that market. The costs also aren't that large compared to some of the larger Mastodon instances, so for the amount of content that it's storing it could be way worse (mstdn.social saved 180 euros when moving to another server apparently but there's definitely other examples of Mastodon unnecessarily ballooning instance costs as it grows in scale, because it's bloatware compared to what's out there. mstdn.social is also a fraction of the activity size of the ATproto network's output on off-peak hours, so eh).
I will say that this isn't a core attribute of the Fediverse, the base protocol is only slightly less extensive and modifiable than Nostr as projects like ActivityPods and "nomadic identities" (over a decade old!) exist which can perform a similar role to an ATproto PDS but with the Solid protocol but it's seen little adoption due to the lack of focus towards implementing "next-gen" features like these in the current set of APub server software.