I think it’s great! If we’re Mr and Mrs MyLastName we know they know me and assumed she was the same. If it’s Mr and Mrs HerLastName it means they know us through her, and assumed she must have gotten the name from me! It’s like putting the name of the company in the email you’re giving the email to, it tracks the source. At least that’s the game we play, because it mostly doesn’t matter to us.
I don’t want to sound like I’m just correcting you for the sake of it, but it’s actually important. Mastodon is the most popular right now, but Mastodon actually wasn’t around at the beginning! Before that was StatusNet, and before that was identi.ca and laconi.ca
So those services already existed, they were the ones built for federation, and so Mastodon was started as another compatible implementation of an existing network protocol. All of that is to say that Mastodon didn’t need to make the right choices at the beginning, and they have already benefitted from this kind of network dynamic! The system has already worked once!