I'm not using it, but for what it's worth and in case this reasoning is applicable to anyone reading, I suspect it could be beneficial for me to (it is common for my buyers to purchase multiple items, and it is also common for my buyers to message and ask about bulk quantity discounts). So, I suspect that my buyers would use it, and it would cut down on messages asking for volume discounts, which is appealing to me.
The reason why I don't use it is because in my categories (craft supplies), 2-4 items isn't volume buying (a lot of buyers ask me about "bulk" discounts, but when pressed for how many they are interested in, it's always 2 or 3). 5 is getting closer, but 10+ is where I can actually provide some savings that isn't a token gesture.
eBay won't let me set quantities myself, if they did and I could make a discount kick in at around 5 items, I'd be more inclined to use it, but in their wisdom they just have it on 2, 3 and 4+.
