Yes, swingweight matters. Swingweight isn’t the actual weight of the club, it’s where the weight is distributed. If the clubs in your bag all felt differently, you would be adjusting your swing for each club to compensate for the imbalance through the set. If you never had a set of irons that was,for instance,weighted at D2, and all the clubs were randomly weighted, you might get used to it, so in that sense perhaps not. If you’re used to having clubs swingweighted properly your 8 iron will “feel” the same as your 5 iron etc, so one won’t feel heavier than another when you swing it in terms of weight distribution. Clubs aren’t the same raw weight, but you want them to feel the same in terms of where the weight is when you swing them. This can be controlled by swingweighting them properly. Why wouldn’t you want consistency in your clubs, get consistency where you can have it, as so many aspects of the game can fall to the random.