The fact that you only get this if you are a resident of a single state is part of my point. The law is good, but having each state exert its own rules is a lot of regulatory friction.

There's only regulatory friction if a company is dragging their heels with regards to compliance and putting in extra effort to comply only with the letter of the law rather than the spirit of the law. For example, once you've implemented Click to Cancel for one state, it is less work to provide that capability to all of your customers than to keep track of who you are required to offer it to.

So when a company chooses the more complicated route to minimal compliance, that's strong evidence that the regulation in question is effective at reducing their illicit gains and would be effective elsewhere.

Once a few do it, it’ll be more likely:

1. that it may be cost effective just to do everywhere

2. that federal legislators will take note that it is popular

A lot of new laws in the US gain popularity at the state level before becoming national law.