The truth of this bender board is that it is not necessary. Seriously, what it is supposed to accomplish there that the curb should not already be doing? That stake wedged between the curb and the bender board to the upper left makes it seem even sillier than it already is. I realize that bender board is designed to bend, but this just draws attention to bad design. Perhaps this is one of those rare situations in which the stake should be on the inside, with the bender board screwed onto it, like might have been the intention for the unattached stake to the lower right. Heck, the curb does almost all of the work of holding the bender board in place anyway.
The dyed chipped wood to the upper right of the bender board seems to rely on the bender board for containment. That would be a realistic application for bender board in a situation that lacks a curb. For this situation, the curb should be adequate. If the soil below the chips is too high, it should have been excavated to a lower level prior to the installation of the chips. As one can see in this picture, such excavation would have been minimal.
Bender board certainly has practical application, such as separating chips like these from turf grass or ground cover. It might contain or provide a neat edge for vigorous ground cover. However, it does nothing that a curb does not already do. In some landscapes it merely adds another component to an innate tripping hazard. It gets dislodged or damaged if vehicles drive over it, or if enough people trip over it.
Unfortunately, for so-called ‘landscape professionals’ it is too easy to install; and such installation is too lucrative. Simplicity is much less lucrative.