Sure, it has advantages, but it is less secure than downloading a binary, since you can check if the binary is downloading stuff off the internet or not, while the repo could be benign today, but malign tomorrow when the company hosting it gets bought, for example.

Also, from what I've seen, custom updaters are still the most common way of delivering updates for Linux outside the distribution-maintained official repo, as most people ship software for many distributions, and maintaining one repo per distribution quickly gets annoying. Ironically, this wouldn't be a problem on Windows or MacOS, if they decided to include a package manager with support for custom repos (the app stores allow side-loading, but do not allow custom upstream, as far as I know).