It'd definitely incentivize having more than 1 of every skin and unlocking all the variants- like the Magepunk knife has different colors that go really well with different agents but most of the time I won't know who I'm going to play ahead of time. If I could equip the green one on Viper, the purple on Reyna, etc, it would be really neat. It would also help getting all the battle pass skins in use, and would get more people wanting to buy the battle passes in the future even as you start to get a skin for every gun