It's not just unsubscribe. They let you turn off emails for an hour, a day, etc. Really convenient if you're generally interested in notifications, but just need a little break.
Another example: when you change your password, Slack will send you a special link to sign-in on mobile so you don't have to type out your new password on a tiny keyboard.
Another example: when you change your password, Slack will send you a special link to sign-in on mobile so you don't have to type out your new password on a tiny keyboard.