When you use a plastic or clay pot and the roots hit the side of the pot, they start turning in a circle creating a root-bound plant. With these fabric pots, instead of circling, the root is "air pruned" - it stops growing and new roots sprrout from the plant's center. This creates a much more healthy, strong, and easy to move into the ground plant.
Fabric posts are also much easier to store between uses - just fold flat. No more leaning towers of used plastic pots falling down and making a mess!
These are made in China and MUCH less expensive than the US made version but work at least as well. They also have seamed edges so a little stronger and keep their shape better.