None of what I’ve said is provided out of the box with apt/deb, and they can only be done in ways that are way to much complex for most non-technical users and in some points they require more work, and some things are simply not available with apt/deb, like the possibility to isolate dependencies, app confinement at the level snaps provide, the possibility to use the same package on other distros (including those that don’t have apt/deb) and different versions of the distro (same package will work on old and new versions independently on how it was built…
This example of the chromium really shows that unless snaps or other similar format was used, applications would have to be sometime very heavily patched to work on older versions of systems to the point that it generates so much work that it would not be worth do to it otherwise, or at least not worth when the snap option exists and doesn’t require that much more work.
Storage is not an issue, I’ve explained why it’s not. There could and should be improvements on that area, but this is not a relevant issue. Progress is made of compromises, this implies that we have to consider not only disadvantages, but also the advantages. Advantages do very clearly outweigh disadvantages. This doesn’t mean it perfect, or that work shouldn’t continue to minimize and reduce the disadvantages, but just considering disadvantages is not the correct way.
The benefits for developers do reflect on benefits for users, with more software delivered faster and more securely.