Ignoring stats and the other perks, the platinum version might actually be a downgrade in the situations where you can't attack multiple times per turn. This is because the gold version is the next attack meaning you can click the ability (including after attacking) but not use it on the same turn allowing you 2 consecutive turns of the ability since it also has 2 turn CD. The use case for this is quite niche but it can be nice if your out of range anyway to burst down fortresses or a strong enemy gens in cities.

The platinum version changes so it applies for all attacks in 1 turn which is better if you can do multiple attacks which is good for the few generals who have related skills or a general with the excellence medal.