Snap taking a dump into the output of "mount" alone is reason enough for me to hate it. I want to see my drives, not that three bundles of libraries are separately mounted into "firefox snap dir" and three others into "snap base package dir" or whatever. There are other offenders, but Snap is the worst. I resort to "df" these days, but it doesn't show filesystem type and mount flags.
No way. Flatpaks are clearly represented in the software shops of their adopted distros (I use Fedora and Pop!_OS, both of which use Flatpak).
From the software shop GUI, I can choose flatpak or dnf/apt from the dropdown. From the command-line, flatpak has its own commands (vs. apt silent under-the-hood behavior).
Flatpak is better than Snap. I use Flatpak for commercial software (Discord, Steam, etc.), but it remains my choice as a user.
The point is totally different: the purpose of both is upstream-managed distribution, consider individual distro like a container ship to be loaded, something not to care about, a commodity.
We know the arguments: often distro packagers are late to update, some projects are very complex to be packaged and demand gazillion of resources to be built, upstream devs on contrary will surely keep they project package up-to-date, sandboxing is good for safety etc. BUT we also know the outcome: 99% of such packages are full of outdated and vulnerable deps, they are themselves mostly outdated, since they are not packaged by the upstream devs who just publish the code as usual, and they have many holes punched here and there because a browser that allow to download some files but you can't open them in other apps is useless, as a pdf reader who can't read a file because it's outside the right place. Beside that you get a 30+Gb desktop deploy instead of a 10Gb, dab performances, polluted home directory, very scarce ability to automate AND all of them still need a classic package manager since they can't handle the base system.
So why them? Because SOME upstream do not want to allow third party distribute their binaries, they are commercial vendor. They NEED such system to sell they products ensuring they can work as a cancer in an open ecosystem, not designed to be a ship for something but a unique individual desktop anyone tune as he/she want.
That's why they are crap.
The next step to classic package management is the declarative/IaC one, like NixOS or Guix System. Those who want Snap, Flatpack, Appimage, ... just want Windows, with all the bloats and issues of Windows.
