Holy Champion and Unholy Champion are abilities that both cost 10 points and effectively increase hero's Attack and Damage by +2, which is a lot (two times more efficient than simply levelling up those stats).
However, they are also available as a spell that costs 25 mana to cast and 8 mana per turn to support. When playing a campaign, skill points are actually an a lot more rare resource than mana, as hero level is very limited. I typically leave skill points for much better things like Cold/Lightning Strike, Life Stealing, Parry, Charge etc.
Is it worth it to get permanent Champion ability using skill points?