So lets fix this really not intuitive UX for drupal console and how to install it.
So what you need to do as of 2018 is to have drupal console installed per project, so we will use composer to do that, lets write
composer require drupal/console:~1.0 \--prefer-dist \--optimize-autoloader
with that we add drupal console to our project, but this means nothing yet as to run it we need to add global launcher so we do that with this 3 lines of code.
curl https://drupalconsole.com/installer -L -o drupal.phar mv drupal.phar /usr/local/bin/drupal chmod +x /usr/local/bin/drupal
when this is done, you can run (run it in /usr/local/bin not in drupal folder)
and just move on and start using drupal console with "drupal" command. Was that hard? No :)