Was G3 a battlecruiser or a fast battleship?

Should G3 be regarded as a fast battleship rather than a battlecruiser?

The argument favours calling it a battlecruiser in its contemporary setting, while allowing that it could be developed into a fast battleship.

The classification argument judges armour against contemporary weapons. Protection that resembles an older battleship's armour could still count as battlecruiser protection against more powerful guns. G3 could be developed into a fast battleship, but the preference here is to retain the battlecruiser label alongside the much more heavily protected N3. Comparing G3 only with earlier dreadnoughts misses that relationship.