@thatguythere I figure that depends on if there is possible 'synergy' between skills or if the system rewards different skills in different circumstances that can change at any given moment.
I mean to use a combat example, in a lot of game systems it does not really matter much what melee weapon you are using, a knife, a sword, a club, etc. Maybe they have slightly different stats, or one is clearly superior to another, etc. A lot of games then inexplicably have separate skills for them.
In that instance yes, there is no reason to take Sword 6/Polearm 6 guy over Sword 8 guy.
But what if poleaxes are awesome vs people in heavy armour and in open spaces on foot, but you cannot use them on horseback or easily indoors, plus they are a pain to carry. Swords are easy to carry and great vs people without good armour plus take up less space. You are going to storm Baroness Von Evil's castle to rescue the sexy prince who was kidnapped and is being forced into marriage.
In a lot of systems you obviously take Sword 8 guy, because Sword 8 guy is better at fighting. If different skills actually let you do different stuff though? Sword 6/Polearm 6 person might well shine over Sword 8 guy when you fight Baroness Von Evil's demonic knights in the courtyard then be less effective after you hack your way inside and battle up the stairs of the Evil Iron Citadel against tentacle demons.