I already have an Amazon account. Why would I go out of my way to get a different account just so a few pennies of my purchase can go somewhere different? I do

I already have an Amazon account. Why would I go out of my way to get a different account just so a few pennies of my purchase can go somewhere different? I don't think the "leave it to the users" option really works here. A lot of people will choose the least-work path.