My company makes sustainable packaging, and the primary way we compete as a sustainable bag product for our food grade division is eliminating the CO2 costs associated with shipping overseas (most reusable grocery bags are made in China).
As a result, it takes around 600 of our paper bags to be as bad for the environment as one reusable bag.
While overseas shipping is necessary and as efficient as it can be (so far!), it is still a major greenhouse factor (so far!)
Also everything that touches a container ship ends up on a truck at some point, so there’s not really any savings there.
Fingers crossed for the Golden Age of Sail Part 2: Wind Boogaloo, even if it hurts our bag division a bit. The net gain is too good to ignore