One thing that is very obvious is that they biodegrade. Even if they're equally bad for the environment in the short term they're not a problem that will take 1000 years to go away.
For example - "Paper bags have a much higher global warming potential (GWP)." (http://www.allaboutbags.ca/papervplastic.html) but when you scroll to the bottom of the page you see "Content compiled by the Canadian Plastics Industry Association.".
Paper bags are not 250 times worse.
https://www2.mst.dk/Udgiv/publications/2018/02/978-87-93614-... page 93