Depending upon the triggers, you can send various types of automations, like,
Send an email when someone joins a list
Send an email based on a subscriber's date field
Send an email based on the date anniversary of a field
Send an email when information in column changes
Send an email when someone enters a segment
Send an email when someone exits a segment
Though, a trigger initiates automation but you can decide when exactly the mail should be sent.
For example, you may want to send company profile after 2 hours of new subscription.
Select multiple contact lists and/or segmented lists on which automated mails will be sent.
Detailed in-site of the running automation helps you to understand your subscribers more accurately.
Depending upon the triggers, you can send some beautifully relevant mails to subscribers