They work. Use a geoweb and plat in the squares. I've used willow shrubs, and prairie grasses with good results. You will want to talk to local horticulturist for the best plants for your site.
dicksewerrat, thanks for the replay.
I am pretty sure that any possible shallow soil is more likely to be reinforced by specific species like prairie grasses. With this type of vegetation, I can understand that the vegetated soil behaves like a composite material because the roots are relatively small and heavily distributed. However, at deeper locations and with using different plant (e.g. willow), I am not sure what the mechanism involved.