I think the first is "how friendly nostr clients to new users" If even 'grandma' can use it easily then it will encourage more users to come. 😄
The second is "how to discover content and people easily". It is probably better if the client already has built-in features instead of users have to use manually external services or tools like nostr.band or nostr.directory
The third is "why the post only about bitcoin, nostr?". Well, this is depend on current users, it will be more interesting that if more users share various topic in the timeline.