achow101, one unintended side-effect is that spending from that address reveals that you're using bitcoin core. but that can only be an issue if someone learns your xpub, which should not really happen normally anyway
It never gets given out, so it's unlikely anyone had every received at their seed before
is it really necessary to preserve this feature/bug when upgrading to descriptor wallets?
oh, you mean when upgrading an existing wallet... perhaps that exact part not, but it's easier to reason about if it exactly maps things
a newly created descriptor wallet shouldn't have such silliness though!