It might be nice to have an anonymous ID that can forward to a (possibly changing) underlying address. But I'm not sure that's the presented use case.
I wonder why real-life mail doesn't do this. Identifiers mapping to whatever your current address is. PO Boxes exist, I guess, but it's not quite the same.
I've had the same exact thought for a while. "DNS for physical addresses" would be so useful for both privacy and convenience.
I am still working on it and in a couple of weeks you can change your handle, add random handles and change your email address. I am also thinking of adding basic statistics and improve the UX for people visiting the links/pages. Since that is also a big problem when using mailto-links. And some more UI sugar to make it look nice :)