Would Enigma expose a concentrated German sortie?

Would Enigma codebreaking have a major effect if Germany waited and sent a concentrated battleship force?

Not necessarily, because a close formation could use flags and flashing lights instead of radio, although Lütjens might still transmit.

Enigma intelligence would matter most when the force transmitted useful radio traffic. Ships operating close together could communicate by flags or flashing-light signals instead. Lütjens might still use radio more than was prudent, creating some opportunity for interception. The answer distinguishes breaking a cipher from obtaining a message whose timing and content reveal the fleet's movements.