In practice I just skim through these 10 messages in such small groups. There's the opposite problem with threads, with which it's easy to miss messages you care about, and harder to have a single topic at a given time. Being able to reply to individual messages also makes the transition from one topic to another smoother.

I can definitely see the problem if you try to use Signal like you use IRC, with big channels with 100+ people and very different topics, not all of them relevant and with people you care about, and I still use Matrix / forums for that.

> It's just what happens in real life : people move around 2 meters when they want to talk about something in particular, and other people can either ignore, either join the ephemeral group.

It really depends on the setting, that's only if you're standing and even then, if you're having a meal sitting at a table, I'd be surprised to see this.