th3g3ntl3m4n it would not be technically possible to install directly from the original source so that so are the dev program that update directly?
That is what makepkg and kcp (a helper that uses makepkg for building and packaging) do, the PKGBUILD pulls/download from the official source (it can be the website of the author, github, or any other cvs repository), then compile it and finally packaging the software to be ready to install in case it's free & open source, if it's proprietary then it comes to download binaries (usually), making easy to track the files installed and manage to update, downgrade or remove without hassles.