@chanath I think you’re missing one of the key reasons why we’re keen on snaps.
Chromium is an open source application, which has been packaged as a deb and is in the “universe” section of the Ubuntu repository. That means it’s “community supported”. Compare that to the Mozilla Firefox deb which is a default application on the Ubuntu desktop and is thus in the “main” section of the Ubuntu repository.
That means Canonical have a commitment to maintain the Firefox deb in the archive with security updates - because it’s in “main”. There is no such obligation for any package in the “universe” section. So you’ll notice that Mozilla Firefox gets regular and timely security updates. Universe packages are maintained by the wider community, which includes people who work on the various Ubuntu Flavours. Chromium is one of those debs. It’s not in main, so there’s no obligation to maintain the package, but we have done for some years now.
Every time there’s an update to Chromium, whether security or just a new upstream release, someone needs to ensure the new version builds. This is not a trivial operation. It’s not as simple as just changing one line from “66” to “67” and you’re done. There’s build failures to contend with, new dependencies, new compiler requirements and so on. It’s work and someone needs to do it. Right now, a Canonical employee is the main person doing that. They need to update the package not just for the 19.10 release currently in development, but all supported releases. That includes 19.04, 18.10, 18.04 (LTS) & 16.04 (LTS). That is a LOT of work.
Making a snap means one package which works on 19.10, 19.04, 18.10, 18.04 and 16.04. That’s a tremendous amount of effort saved.
The fact that a snap is a single file on the filesystem is a technical detail, and is a good thing. When you install a snap it’s a single file that gets mounted on boot. When you remove that snap, the file is unmounted and gets deleted. No files left lying around on the filesystem, it removes cleanly.