Thanks much for your extensive response.
Great to read the abuse factors are known and is handled.
I do very much hope it'll work out.

Advertisers are key indeed, donations may be another revenue stream. The latter will never be large, but perhaps some people around with a golden heart and the drive to contribute to decentralised solutions like 3Speak is.

For users, content is key. The more content, the larger the variety, the more users will like it.

UX: I am not a regular 3Speak user, so I can't tell. What I do know, for a larger audience, the UX must be similar to YT and the likes. I, for one, used to listen to podcasts using Fountain app on the Nostr network. For different reasons incl the app having some features that I really liked in terms of scheduling the playlists, the idea of using a decentralised service and as a bonus earned some sats (latter wasn't the reason, but I saw it as a really nice bonus; the USD value was more like a few dollars annually while listening at least 2 to 3 hours daily, therefore listen-to-earn wasn't a thing for me at all).

After using this app for more than 6 months, I switched back to Spotify. Why? Because the app UX wasn't good enough. Fountain crashed to often, it failed to load often enough the latest new episodes for the podcast series I was following. Spotify is (almost) always good in these aspects, plus they added features not too long ago why I started to use Fountain.

Long story short, what I try to say regarding UX is: Whenever one thinks UX is good, reassess and improve. Since UX is a very short 'word' but it is what makes people walk away after the novelty wears off, or stay.