Small-tube boilers and the end of the battlecruiser split

Was the proposed small-tube-boiler ship intended to replace the older 12-inch-gun capital ships?

It was a trial for the next generation rather than a direct replacement itself; success at about 28 knots could remove the need for separate battleship and battlecruiser types.

The proposed ship is best understood as a test of the next capital-ship generation rather than a direct replacement for one older class. If its small-tube boilers delivered battleship protection at battlecruiser speed, the Royal Navy would have to reconsider maintaining two separate types.