www.bbc.co.uk/news/uk-47022534
They are going to charge more for them than for a plastic bag and they cost more in terms on CO2 emissions and energy to make them but decompose quicker. I can't see many people paying more for a paper bag really.
I prefer them because they are not going to end up in the ocean stuffing turtles etc but I'm not convinced that they are good idea from the CO2 and energy perspective and think people won't buy them because they cost more.