if you have configured an email channel on Zammad to send/receive emails, your clients can simply reply to the email they get from the system and this will update the ticket as well. There is no need to access the web interface to reply to tickets…
You are right, there is no need to this, but our customers only use the web interface and never answer via email. They want it that way.
They want to answer per Email in the web interface to inform their colleagues if there are any news.
We mostly use the email channel but also use this option when we have the web interface open.
When you hit any of the “reply” options you can add recipients as you see fit. Usually, reply-all contains the wider audience