Well if it were closed source, it would be harder to repackage proprietary apps because you would not know how the snap “root filesystem” translates to $DISTRO root filesystem.

Because some apps are only packaged as snaps so if you want them to be accessible to users, you have to install snapd. Flatpak can still be the default which on non-Canonical distros already is. Which why I don’t even worry about snap becoming the standard.