The plastic can holders that you refer to are called PakTechs, and they actually come shipped together with the beer, within its carton. We have no control of how our breweries produce or package their beers for international shipping, but we're doing our part by reusing the PakTech holders to pack your order.
The benefits of doing so are: 1) We can prevent one-time usage for this plastic material, 2) They are extremely useful in securing cans and preventing them from shifting about or getting damaged during delivery, and 3) They help us work more efficiently during the picking process of packing for your order. We assure you that PakTechs holders are made of 100% recycled resin, are extremely recyclable, very reusable, and comes with unique design that helps assuage certain environmental conflicts. No more fishes getting stuck in plastic rings or bags!