It looks like I was right: https://github.com/pop-os/cosmic-applets/pull/282
20MB for every simple application is a lot, and multical binaries won’t be an option for third party developers.
This is still worth the much better DX of using Rust though.
I wasn’t thinking about applets but more about full-blown libcosmic applications.
Gnome Circle bas a lot of very simple apps that do just 1 thing and weight a couple MB each at worst.
With iced such an ecosystem would be at 20MB per app, so simple " don’t 1 thing and do it right" apps would be less scalable. And I doubt you would want to have all of gnome circle as a multicall binary.