If the script fails halfway? Good look trying to undo whatever it did if you do not have access to `zfs rollback` or similar.
It is also less-than-fun to go through `zfs diff` and the downloaded script to make a package out of it that can be distributed and automated.
There's a million things that the script can do stupidly, and practically every single one has at least one assumption that is bad.
One trick I've learned is to edit the script before running it and prefix anything that looks dangerous with "echo" (because of course none of them ever support --dry-run). Then I can at least see what they are doing, what they are downloading, etc.
curl|sh is the bane of my existence. Shame on you if that's your only means of installing.
You should redirect your anger away from curl and pipe and toward using install scripts vs package managers in general, because that's where your beef really is.
Even so, windows style binary installers are at least frameworks designed for installing stuff (many with years of bug fixes under their belt), while the curl|sh style installers are just ad-hoc one-offs written in a language that's known for being pretty hostile to defensive programming.
So yes, any installer could make those errors, but in my experience only random shell installers seem to do that. Saying they are the same is a false equivalency in my eyes.
The only installers I can think of that aren't auditable are binary installers. If you meant something else, I'm not understanding.