Legalize option to pay more for your food to reduce animal suffering

A Kurzgesagt video says that even paying a few percent more for animal products can greatly reduce suffering. But in practice you're not able to pay this few percent more, because whenever you go to a busy restaurant, or even a grocery store full of confusing labels, no one has the time to research every single thing. (Kurzgesagt admits there are great inefficiencies here)

So one idea is a law that forces businesses to take this extra money people pay them, and use it to reduce suffering. They can use this money to help them comply with the law, so it shouldn't cost them extra. But they cannot just pocket the money.

Is this a win-win?