People always say you can simply pour ingredients into the mix bottle. Theoretically, you can. But there’s no way I can accurately stop pouring vg from a gallon jug. Or nic from a 240 ml Boston. Maybe some people can, but I’m not one of them.
If my flavors are small bottles with dropper tops, I’m accurate enough with those. The pg, vg, flavors in 120 ml bottles, and nic I still need to use some sort of measuring
device, whether it’s a syringe or graduated cylinder or whatever. I’m not getting out of washing up, at any rate.
It’s somewhat faster and I usually get good consistency. Otherwise it is no more simple or in any way better that I can see. I think it’s very much down to personal preference. Folks should give it a try, especially if they struggle by volume. But one method is not better than the other.