Fastmail has one feature many others lack (which is hard to research unless you want/need it and have go down the rabbit hole) - scope limited login tokens for specific uses. Specifically, you can set up one for “read only IMAP” (to archive emails using scripts etc.), “SMTP only” (to send emails from scripts like backup reports etc.) and so forth. Many, if not most, other providers either don’t have it, or if they do it’s very limited like one token only with no scope control. $0.02 hth