The goal is to eliminate trash in the environment. Thin plastic bags get discarded carelessly, then catch in the wind and get strewn around a wide area.

Plastic bag bans have been sufficiently successful that people have forgotten this was a problem.

If the goal was reduced emissions, these bans were an abject failure. Single use plastic bags are really efficient from an energy use perspective. Their replacements take significantly more energy to produce and the re-use is unlikely to ever balance out, as they often require hundreds or thousands of uses to be equivalent to a single use bag.

Great! Can you show me the numbers that make you think that these bans were not effective?