What's the advantage of using Git submodules for Drupal core and contrib?
At our workplace we avoid git submodules as they add unneccessary complexity to the system.

We run one git repo for each site, and we have drupal core as an upstream remote. This makes merging in 7.12 for example as easy as:


git fetch upstream
git merge 7.12


As for contrib, drush is king


drush dl views
git add -A
git commit -m 'bumps views to next stable'


Hope this helps