Based on search results the default deployment method in the Ruby world is something along the lines of Capistrano. The application server checks out the source code, installs gems via Bundler, precompiles assets and runs migrations.

This setup requires Node.js, Ruby and bundler installed on every application server. With Go you can build a single binary and only push that to the application server. Less moving parts makes a system more stable and robust so that’s a big plus.

It could be possible to achieve something similar with Ruby. Deploy a single directory that contains a Ruby binary plus all required gems. The first challenge is probably correctly building gems with native extensions for the application server.