Something like Clubhouse is a nice feature to existing social media platforms that help people with a following to have ad hoc conversations.

Other than that easy to copy, it has no moat, and it solves a problem of a minimal number of people.

As far as I see it, Twitter and Facebook already have something similar in place.

Call-In, the idea of the hosts of the All-In Podcast, looks to me more like a viable business. Their vision is to give everybody a quick start to podcasting. No experience or team is required to get started. It looks like a promising sustainable vision to me.

Just bear in mind a feature isn't a product, and a product alone doesn't make a business.

My two ct.