Another example is Fade from Sight: Having level 5 is only useful if you stay invisible for some time; if you just want to turn invisible for a second or two during combat, you're better off having level 1. In a system with 10 fireball levels, any invisibility spell should have several levels as well, so it can't be mastered spending just 1 skill point, but that means the effects should somehow become better, apart from a lower mana consumption rate.
If you are playing a warrior, FFS is actually one of the best spells in the game and you would absolutely want it at top level.
The warrior's special move is a non-targetting attack, so does not break the invisibility, and the combination of the two is the easiest way to take down Josaria in the game <img src="/ubbthreads/images/graemlins/smile.gif" alt="" />
And yes, working that out came as a huge relief to me after who knows how many deaths at her hands <img src="/ubbthreads/images/graemlins/biggrin.gif" alt="" />