There are places where a low wall is appropriate
at a change of level.
A change of level railing is a code requirement for safety, but there are places where a low wall is appropriate. This detail shows a railing wall at an orchestra pit; but with some modifications, it would be suitable in many other interior locations. The detail relies on a substantial wall forming the change in level so that there is adequate anchorage for the structural angles that give it rigidity.
This railing can be curved, but that greatly increases the complexity for the contractor. NOTE that in most situations, the height would be required to be 42"! Not the 40" shown here.
The decorative finishes have nothing to do with the structural concept. In other situations, painted drywall would work just as well. In a straight railing, a continuous steel tee could be used in place of the curved double plywood top plate.