The pac CLI is "xcopy" (or in the macOS/linux world more appropriately, "cp -R") installable, i.e. it's sufficient to unzip the downloaded macOS or linux nupkg into a local folder, and call the executable from that location.
This is also what our CliAcquisition.ts code does within our VSCode extension; unfortunately, the .nupkg does not capture/restore the +x file attribute, so make sure to `chmod +x pac` the pac executable (see line 89 in that same file).
For most users, we don't advocate or advertise to run pac CLI directly from the .nupkg, but it is supported since we leverage that mechanism ourselves (not only in the VSCode extension, but also in our GH Actions and AzDevOps tasks).
Our reservation stems from the extra setup steps needed like chmod, but also since the pac CLI won't auto update itself.
If you see pac CLI issues beyond the chmod, please do report issues on our VSCode issue tracker:
https://github.com/microsoft/powerplatform-vscode/issues
