The uselessness of a few skills

Since the moment I reached the required levels to get Frostblade and Distance Shrink skills I keep wondering what are the advantages of these few skills.
Frostblade doesn't change anything - doesn't increase my attack the way cleric's buff for increased magic attack does. Its description says it should increase attacks but it doesn't. Before and after buffing myself with Frostblade my M.Attk and P.Attk both remain unchanged. For this skill I can see only disadvantage which is to waste spirit and coins on it.
Distance Shrink is that much useless as Frostblade because character doesn't move faster with it, not to mention that it wastes the so priceless Chi.
Another useless skill whose purpose I still can't understand (other than wasting coins and spirit on it) is that thing which restores 10% of one's mana bar. I forgot its name. Before I get to the level and awareness for buying it, I was looking forward to get it. But when I read it requires 2 sparks to recover only 10% of my mana bar (which means the miserable ~800 mana points), I regreted I was waiting for it.
And there's one more skill which would be very useful if it didn't suck out 60% of one's health points. I forgot this skill's name too - after all I don't use it (yet). I'm talking about the skill that sucks 60% of hp, causing a bomb-like explosion on surrounding enemies. Why the devs would think someone would risk dying in the matter of seconds after using this skill, losing 60% of his own hp and also taking the damage from all affected mobs when they realize who attacked them?

Do you use these skills and for what? As for me, I can't see any advantage of having them.
The purpose of this topic is that I find out what are the advantages of these skills and decide should I waste coins and spirit on them. I'm getting closer and closer to the point I'll have almost all available skills at lv 10 and that makes me dream about new skills.