Purpose of Abilities Accuracy?

Although I usually spend my FE's on Entrances, there are still sometimes when I'll spend some FEs on Special Abilities.

Is there any special reason to spend money on the Accuracy of the Ability versus just spending money on the Skill? What factor does the Accuracy % play in everything?

all accuracy does is determines the chance that your special ability will activate. The higher the percentage the better the chance that it will activate