There is a difference. The Minotaur Guardian (from "Heroes 5") will always deal two hits to the enemy, while the Orc Veteran (from King's Bounty) will only do so if there is a counterattack! The first happens quite often, but I've only seen the second in King's Bounty.
You wouldn't argue that Succubi shoot fire, would you? Throwing bones is a dubious option, but the description mentions such a theoretical possibility.
The bone-throwing option is very silly, especially considering the unit's characteristics.