I think of this feature not as “scheduling an email to be sent at a specific time”, but rather as “deferring sending the email for a period of time”. Ironically, I tend to use this tip more for personal emails than work emails (since I try hard not to check work email outside of business hours). Scheduling lets you define a slower pace of email communication, reduces some of the anxiety around sending important emails, and allows you to maintain your expectation of working hours.