slightly confusing docs on bundler

[mwk24]

The doc says:

Gem Support
Solargraph is capable of providing code completion and documentation for gems. When your code uses require to include a gem, its classes and methods become available in completion and intellisense.

You can make sure your gems are available with the commands Build new gem documentation or Rebuild all gem documentation in the command palette.

Solargraph and Bundler
If your project uses Bundler, the most comprehensive way to use your bundled gems is to bundle Solargraph.

In the Gemfile:

gem 'solargraph', group: :development
Run bundle install and use bundle exec yard gems to generate the documentation. This process documents cached or vendored gems, or even gems that are installed from a local path.

In order to access intellisense for bundled gems, you'll need to start the language server with Bundler by setting the solargraph.useBundler option to true.

I'm finding this hard to understand. It says: " When your code uses require to include a gem, its classes and methods become available in completion and intellisense.", but then is says: "the most comprehensive way to use your bundled gems is to bundle Solargraph". These seem contradictory. How can the second way be more comprehensive when the first way already works. What does comprehensive mean in this context?