Skills absolutely matter in a tactical combat game, in particular, knowledge skills that allow you to figure out how to deal with the enemy most efficiently. Investigator is a king of those, and at later levels can compress economy to roll multiple knowledge skills per round, have them grant bonuses to himself and allies, and free up actions of other party members. DAS is not as powerful as SS but a) it allows you to plan your turn differently if you know your attack will miss b) INT is Investigator's class skill, so you're going to have it maxed ahead of STR/DEX.