> If I've participated in conversations on 5 different topics that have moved on, it can sometimes be tiring to have those old threads reopened with more discussions.

I reckon that’s more due to reopening old conversations regardless of whether it’s threaded or not. In fact, I feel threads make it easier to return to those conversations again: your message is there in that side-chats history and not in some global history where now people are scrolling back-and-forth to remember the prior conversation.

> It's like having 3 text conversations while also being out to dinner with friends.

Threads are like 3 text conversations + a vocal conversation. Not having threads is like 4 vocal conversations all over each other.