I don't think most people need to read everything they receive, but in my role as the project leader of a large open source community, essentially every conversation in chat.zulip.org is potentially relevant for me, so skimming every conversation is useful.
The critical thing here, both in my daily work and coming back from time away, is that Zulip makes skimming really cheap (`n` to jump to next topic, then read a moment and then hit `End` if it seems likely that the thread is resolved to check the conclusion, and then repeat). So a 150-message thread debugging something takes like 30 seconds -- read the first post (maybe a bug report), note who was helping investigate, jump to send and see that the topic ends with a PR link or other resolution.
At the same time, Zulip's organization means I could find the dozen of threads that might be a short thread presenting a question or problem that I'm our main expert on. In these cases, I can read the thread carefully, and send a reply resurrecting the thread (2 months later) with answer that was missing, some added context/background, or a link to a PR I made to put the answer in our documentation (my preferred solution to unanswered questions).
This has the effect of unblocking a bunch of useful work that had been waiting for me to return, and also giving me good context on everything I missed.
It's also pretty fun to see all the great that folks did while I was away :)
Backing up from the special case of a paternity leave, what's important here is that with Zulip, catching up on conversations you missed is an efficient use of your time, which it really isn't for other team chat tools.
Essentially everyone has miniature versions of the catch-up problem:
* Fulltime employees coming back from a normal 1-2 week vacation.
* Anyone working closely with collaborators in other time zones (I wake up every morning to a couple hundred new messages in chat.zulip.org sent by our international community members).
* Any leader who spends a lot of time in meetings and wants to focus on the meeting and then batch-process communications afterwards.
* Any engineer who wants to be able to spend a whole or half day focusing on a really difficult problem and catch up on conversations afterwards.
* Anyone who's a part-time participant in an open community, whether they just check it once a day, one a week, or once a month. A user in this situation really wants to skim everything that happened and find what's interesting to them, not read the last few hours' traffic, which is what the Slack/Discord/Teams model forces you to do.
The same technique core works for all of these cases: pick your favorite streams and read them with `n` as I described above, then perhaps browse the list of topics in several more and click into just the topics that interest you and then mark the rest (if any) as read.
All IRC-inspired chat tools are a really rough experience for part-time participants -- they just don't have a way to let you prioritize reading interesting conversations. We discuss this issue at length and its consequences for inclusivity of the communities that use them in https://zulip.com/for/open-source/. (It's framed around inclusivity in open source, but the Slack channel model also can exclude leaders who spend most of their time in meetings)
(As a sidenote, being able to do this is why Zulip pushes users to have every conversation in a topic, rather than "threading" being a side feature used for 10% messages like some other tools do.)
Fair enough, and depends on your FOMO -- but with Zulip's topics/threads you'd be the one who makes this call. E.g. you probably want to skip some banter or some operational stuff, but still catch up with the topics you want to catch up -- and at your own pace.
I don't think anyone should be expected to do that but if I wanted to read everything it would be a huge pain to do so in Slack. It is nice to have it as a realistic option.
