Benefits: Catch-All Email Forwarding
A catch-all email forward accepts all email to email@example.com and forwards to an external email address.
A catch-all can be useful if you want the freedom to simply invent email addresses on the spot and have them all "just work" and always go to the same place, without ever actually managing multiple rules.
Catch-alls can also be helpful if you've used lots of different addresses in the past and want to see if email still arrives at those old addresses.
Catch-alls can also be useful to generate dedicated or throwaway email addresses each time you're forced to register with some company. Use firstname.lastname@example.org for your dealings with Canon, for example — if a particular email gets compromised or collects too much spam, it is "compartementalised" and can be replaced.
By default, all new domains have a catch-all forward to your primary email address. You may remove catch-all forwarding, and then any unhandled email will bounce back to the sender as undeliverable.