Why Japan did not send battlecruisers to the Grand Fleet

Why did Japan not send major warships such as the Kongō class to the Grand Fleet?

Japan was already using its ships for Allied duties in other theaters, though a battlecruiser squadron could have been useful.

Japan sent warships to the Mediterranean and supported Allied requests in other theatres. Its ships also hunted surface raiders in the Far East and Indian Ocean, which competed with any proposed North Sea deployment. A Kongō-class battlecruiser squadron could have been useful to the Grand Fleet. Integrating it would also raise questions about senior command within Beatty's battlecruiser force.