So for me, the interesting thing about a service/app like this is the broader architectural question it poses:
How important or valuable to the fediverse will be "middleware" or "hub-like" or "intermediary" services that create functionality between and different from the flat hierarchy of all servers being of the same kind (ie instances hosting users)??
I asked Dansup the same when he first announced this and he said they'll probably be more valuable over time. And I tend to agree (intuitively). All the attempts at fedi search engines, the community/instance finders for lemmy, the user finders for mastodon are all examples of this that have more or less been rather successful. This service from Dansup leans toward nomadic user accounts, which is a big area. It'll be interesting to see what else pops up and if the general idea takes root.