They're often counterproductive. People feel accomplished, and finished with the half-measures and they often don't bother investigating the results or the ongoing requirements.
The evidence is that the major sources of plastic pollution were not put under further regulation subsequent to the regulation of this minor source of plastic pollution, even though the threat they present has not diminished.
It's an article of faith for people in the libertarian climate change denial community, because they get funded by the people who sell the natural gas that is used to make them:
I was visiting San Diego soon after the fees went into effect and they were dealing with a cholera outbreak because the homeless no longer had plastic bags to defecate into. So you have a miniscule effect on plastic pollution in exchange for a large effect in a different area.
This is not salient, it's like saying "when I removed pressure from the wound, the patient started bleeding out. Therefore removing pressure is bad and to fix the wound we should ask
Re apply pressure" The pressure is a stopgap, you need to address the underlying problem (in this case by ensuring adequate bathrooms) rather than simply reacting to the surface level concern.
They did reduce plastic pollution, as you admit.
Was it the most effective regulation to pass to reduce plastic pollution by the greatest possible amount? Not at all