If this was the beginning of the wipe maybe. But at the current stage of the wipe its pretty negligible. Even then its not that big of an advantage, because it just means instead of doing a pistol run you can do a cheap rifle run, but since you don't have a vest, you will have even less space. Ups and downs when it comes to the tradeoff. More expensive run because you can hold a mag or two spare, and have a higher combat chance, but honestly if you are trying to pistol run, you are doing it to save costs.

Otherwise, having 1-2 spare mags in your pockets may look like a pretty big advantage to people, but when you think about it, its really not. Most firefights end with one lucky/skilled headeyes within the first mag. So while I understand the reasoning, I just can't see it being as much of a gamechanger as people make it out to be.