Checking the civibuild create parameters I do not see an option to include the translation/language files? That would be really helpfull, I now add them manually after a civibuild.
What build type are you using, Erik?
Uncommenting the line:
# extract-url --cache-ttl 172800 civicrm=http://download.civicrm.org/civicrm-l10n-core/archives/civicrm-l10n-daily.tar.gz
app/config/drupal-clean/download.sh in your local buildkit will mean that localisation files are downloaded as part of the download.
You could go a step further and submit a PR that uncommented that line in buildkit, but that is probably for another day.