These rules grew out of an attempt to address the well-known "5 minute adventuring day" problem in D&D.  They are somewhat similar in concept to the Reserve Feats published by WotC, although developed independently.  The idea is to give arcane spellcasters an always available magic ability that can be used in combat in lieu of either (a) using a powerful spell better reserved for a more dangerous encounter or (b) doing nothing.  I also include in case (b) actions such as firing a crossbow or making some other largely-ineffectual attack.

The core problem as we see it is that everyone wants to do something every round to help the party.  The role of a fighter or cleric is usually apparent.  But wizards tend to be all-or-nothing.  If a mid-level party encounters a large group of, say, orcs, or some other monster that does not really pose a threat to the PCs, then the wizard either does nothing, or else uses a spell that is not at all necessary and which is often overkill.  In our view, the desire to avoid boredom leads to arcane casters using spells when they are not really needed for party success, which contributes to early resource depletion and frequent stops for rest and repreparation of spells.  By giving these characters a decent (although not overpowered) arcane ability, the characters have something useful to do that retains some magical flavor.  Also, providing characters with this always-on magical attack ability gives them freedom to prepare more useful "utility" spells instead of taking all fireball, scorching ray, magic missile or what-have-you.  In about 18 months of playing with these rules, we have found that they seem to work well -- your mileage may vary, of course.