I don't care about the distro. You can get basically the same thing from Vanilla OS, uBlue, Fedora Silverblue, and many others with just a small amount of configuration.

You use Distrobox from the terminal, but distrobox export lets you install graphical apps in a Distrobox container but integrate them with the host. BlendOS (and Vanilla OS) just combine it into a package manager. It's also not "important and big," it's just a container—basically just WSL for Linux.

Distrobox doesn't work with Android. I was talking about the "install any package from any distro" part. BlendOS just adds in Waydroid support.

No, it does not. It's just Waydroid, which IIRC requires x86 apps.