It's straightforward to set up an apt-get repository that updates nightly and have users use that. For something as widespread as Rust I expect better than curl | sh scripts.
Probably doesn’t matter for Rust but once you start messing with random system packages that other packages depend on it becomes less than straightforward really quick.
One simple version bump can effect hundreds of packages and, if you’re not careful, bork an entire install… ask me how I know that one.
—edit—
Also should say that I’m fully in the package manager camp. If I want to install something that’s not in the repos I almost always find or make a package and build it locally because I don’t want random orphaned files strewn around my system folders.
Unless it’s just some command line program then I usually just use it from the source directory and don’t even bother having it in my path.
For what it’s worth, I had a C# dev who’d never dealt with Rust at all before get themselves setup, and then compiling and running the Rust app by themselves in about 10 minutes flat (our internet is slow) and I definitely think the ease of the setup flow contributed to that hugely, so massive thanks for making it so nice.