Can a collapsible shipping container reduce the environmental impact of transporting goods?

I can't see that it would help all that much. You can only collapse it After Use, ie when it is no longer transporting goods. Maybe there are lots of empty shipping containers lying about but I would have thought they were too valuable for that and will be recycled, ie re-used.
Do you actually mean Transportation Goods or the Transportation OF Goods?. Certainly in the latter case I would expect that the Energy involved and the pollution from that, is the biggest cause of environmental impact. Most of the Smoke is emitted in International Waters where there is no-one to prevent it.

That sounds like a marketing lie by the seller of collapsible containers to me. Collapsed and opened a few times and the container is likely trash for the land fill.  Ridged container can sometimes be used 100 times with only minor repairs.   Neil