The sandbox is there for portability. I don't see a promise of being _more secure_ than other app distribution channels on linux anywhere. Though the packaging & sandboxing model certainly opens a path for improvements in the area.
Is it any less safe than installing something via aptitude or Ubuntu's app store?
The alternative if using Ubuntu is called Snap. It has a sandbox and it is better implemented, at the very least the part about reading and writing in home dir.
As far as I was told, snap sandboxing only works with a specially-patched (and apparmor-enabled) kernel [1], though I am not sure what the current status is.
I would like to know what's better implemented in snap, it seems this is simply a case of most applications requesting a r/w permission in the home directory. It might get complicated sandboxing vs code without that, don't you think? Or at least lead to a subpar user experience.
I am hopeful it will improve, though. Sandboxing needs to become the default.
Is it any less safe than installing something via aptitude or Ubuntu's app store?