Sometimes the reply is ready and the moment isn't. Scheduling lets you write it now and have it go out at a time you choose.
Write the reply as usual, then open the options beside the send button and choose to schedule it. Pick the date and time, and the message sits until then.
Scheduling is deliberately not something the send button remembers. Ordinary sending stays the default no matter how often you schedule, so you can't schedule a reply by accident.
Across time zones — a reply written at 22:00 your time arriving at 09:00 theirs reads as attentive rather than nocturnal.
After a late fix — you deployed at midnight, the customer doesn't need to know that.
Before a planned change — write the follow-up while the detail is fresh, send it when it becomes true.
Clearing a backlog — answering thirty conversations in one burst can spread out rather than arriving as thirty simultaneous notifications.
A scheduled reply is written against what you knew when you wrote it. If the customer writes again in the meantime, or someone else picks the conversation up, the message still goes out as drafted.
For anything that might change — an in-flight incident, a decision awaiting approval — snoozing the conversation and writing later is safer than scheduling something that may be wrong by the time it arrives.
