I could see a good use case for having at least a centralized, cross instance search where the instances will send up community information to the service and then the service shares it out with everyone. Rather than make a new community on my instance I could find the active community and federate it.
Then again the same thing happens on Reddit for popular topics. Like when a new game is announced there might be 5 people trying to start the subreddit for it.
No for one simple reason: I have a wife. We like to experience content together (watching movies/TV, playing games). None of which I can do without not one but two of these things. No thanks.
Jerboa also doesn't do push notifications like the desktop does. So for moderation or messaging it's not super useful since I don't know if I have new applications or messages I should respond to.
That might be a limitation of Lemmy or the app (I'm not sure if it supports push notifications at all)
Not in its current form. Anyone who's tried to start a tech company knows you have to make your solution simple to use. Making software easy to use is actually surprisingly hard, involving experts in user interfaces, a lot of thought on user onboarding and training.
Lemmy as it currently stands is relatively new-user hostile for non-technical users. Content discovery isn't very clear, people are confused about how to find communities to follow, and the mobile apps are barebones.
That's not to say it can't get there, but until you never need to mention that the system is federated, I think a lot of people will be turned off from the complexity of using Lemmy. The community right now is motivated to use Lemmy and I would imagine a little more on the technical side, but getting your parents to use Lemmy or Mastadon would be a challenge currently.