Oil-fired Lions and the path to small-tube boilers

What changes if the Lion-class battlecruisers are designed with oil-only boilers?

Later ships would likely adopt oil firing sooner, encouraging earlier small-tube boilers and perhaps modest speed gains, while leaving most of the Lion design unchanged.

Small-tube boilers benefit from the steady, controllable heat of oil firing, unlike manually fired coal systems. Making the Lions oil-only could normalize that fuel across successor designs and bring compact boilers forward, though the immediate ship would change less dramatically than its technological descendants.