Depending on the implementation, I feel that DIDs across ActivityPub could make the aspect of interoperability between different services much more appealing as well. While I think it’s interesting that we can directly interact with posts from entirely different services like Mastodon, Pixelfed, Peertube, and Friendica, I find it difficult to make the feature make sense for daily usage beyond the convenience of not having to open another site/client for a singular interaction. I feel like it makes sense if you only prefer a single service/format for accessing content, but every software implementation handles content differently, with differing formats, features, and limitations. They each specialize at accessing and presenting the fediverse in their own ways, so there’s reason to use each individual application. If you still have to make a separate account for both instances to interact when using either of them, I feel that defeats the purpose of the interconnectivity aspect. By being able to connect the same account to instances between different software, I think this would strengthen it.
I only find it useful on laptop keyboards. I like the numpad for entering numbers, and I also like having dedicated keys for stuff like Home, End, and Insert when browsing or editing. It saves space when you can double the numpad for both.