Example. I'm doing an online shop and want to buy handwash. A refill pouch of 500ml is €4 but a 250ml plastic dispense bottle of the same brand is on special offer for €1.75. Why not put the refill bottle on special offer? Also, if you got extra clubcard points for buying the refill, which uses less packaging, you'd buy it. They could easily do promotions on products which have a lower environmental impact but just don't bother
And I know that soap is a better environmental choice.