Not OP, but I'm a bit against using cargo (or any other language-specific dependency manager) as a general purpose package manager. It forces me to periodically run updates on many different managers, it doesn't always interface as well with other system / distribution idiosyncrasies as the native package manager, and I don't want to remember or have to care about what tool is written on what language. (Of course, they have their place for specificic use cases, just imo not system-wide installs of random binaries)

So I can see why it's a problem if it works with cargo but not with brew.