Be careful who you trust when installing software is a fine thing to teach. But that doesn't mean the only people you can trust are Linux distro packagers.
But yes, that the run arbitrary scripts is also a known issue, but this is not the main point as most code you download will be run at some point (and ideally this needs sandboxing of applications to fix).
Not what I meant. Getting software into 5 different distros and waiting years for it to be available to users is not really viable for most software authors.
(And when I say fine, I haven't actually used it successfully yet.)
I think distros don't want this though. They all want everyone to use their format, and spend time uploading software into their repo. Which just means that people don't.