What are the benefits of 301 redirect ?

301 redirect is a permanent redirect which is required if the search engine wants to know if that page does not exist anymore and wants to update the indexed value for the same. Having 301 redirects for affiliate links, expired landing pages and other similar pages helps with keeping the bot updated on the page changes.

If you have SSL certificate on your domain. Then it's beneficial for you to use "*" wildcard on the domain for all subdomains with and without www in the domain. So in such case 301 redirects through CMS like say WordPress should be encouraged.

Benefits for having 301 is -

1. To reassociate the URL with a new page as opposed to the expired URL.
2. To avoid loss of traffic for the pages which are no longer serving for the expected keyword from the searches.
3. Setting up perma-redirects before properly moving the content that serves search relevance on the page, helps maximize the authority.