A recent quick guide dedicated to helping video creators to design efficient YouTube ending sequences reminded me of this often neglected aspect of videography: outros. For the record, in YouTube's official vernacular, branded outros are called end screens. They are short static clips that serve as a bookend to the current video. Those end screens will be displayed for a configurable amount of seconds, right before the movie ends and rolls off into the next video in the queue. The goal of those YT-specific sequences is to encourage your viewers to consume more videos within the same brand space. It also encourages them to stay on YouTube. As a bonus, it allows for consistent branding across all your videos if you choose to use the feature.
On the YouTube platform, outros are created from static background images, which have a number of holes or open windows acting as placeholders; you then fill those holes by embedding visual links in the form of other YouTube assets (such as videos, channels and subscription links) or authorized external links.
As you can see from the list of available assets, there's only so much that YouTube will allow you to incorporate in your outros. The goal is YouTube is to trap users into their ecosystem; thus driving your viewers off and away isn't part of the deal. Even if you somehow manage to promote yourself, your services or your products through these links, you'll still be promoting YouTube first, yourself second.
As to whether or not creating outros for your YT videos is a worthwhile investment, it depends a lot on your viewership demo and habits. If you check all the boxes below, you should probably spend some time and resources to create an engaging outro. Consider creating an outro if you:
On the other hand, if you do not meet these criteria, you may as well save yourself the trouble and either: stick with the standard "branding" outros, or else ignore the custom end screens altogether. This will leave it to YouTube to direct the users to what it considers relevant content -- content which probably isn't yours.