But curl|bash is a one step process, as soon as you get the script you execute it, with no opportunity to check a signature...
I'd also argue that secure defaults are most important for folks who don't care. And there are more secure options: the package managers.
So sandstorms installation guide should in your opinion just say "wait a couple of years and maybe someone will have packaged it for your distro"? Yes, that sounds excellent way of getting users. And hey, the most secure way of installing software is not to!