Currently for version 2014.7 (symfony 2.3.21) the option use_controller: true in dev environment doesn't serve the assets via the assetic controller.

In config_dev.yml use_controller is set to true.
Tried to delete the assets from web/css/ and refreshed the page.

The styles weren't found. So even if I use the assetic controller I have to do assetic:dump.

Tried this with a symfony app (2.3.21), and there it works.
Not sure where this behaviour gets broken.