Everyone has been trained for years to do this:
curl http://obscure.url?random-string | sh
curl http://obscure.url?random-string | sh
curl https://url-of-well-known-project | sh
I may not trust the owners of a random domain, but I certainly trust the owners of rustup.rs not to do anything intentionally malicious.wget random.club/rc-12-release.sh
chmod +x ./rc-12-release.sh
./rc-12-release.sh
almost nobody would actually read the script before running it
git clone http://github.com/unknown/repo.git && cd repo && npm install
$ svn checkout
$ ./configure
$ make
# make install
Linux has a very good package management for many years. I see absolute no reason to break this by creating shell installers.