This strategy is being used on smaller streets in San Francisco. It creates a message to drivers that they are in the pedestrian realm, slowing them down a bit. The design also creates a "speed table" which causes speeding vehicles to "hobby horse". This characteristic makes this device problematic to disabled advocates as it can cause pain to people with spinal injuries.
The stormwater falling on sidewalks is considerable. Permeable basins and services can delay or eliminate this runoff from reaching the street and sewer systems. Both permeable paving, allowing for ADA compliant vehicle access where there is street parking, and planted basins can be used. They make the street edge of a building much more attractive as well.
This type of treatment slows and allows the infiltration of storm water, while still allowing ADA compliant access.
The concept behind a green stair is a stair so nice you want to use it instead of the elevator. In a perfect world it has plants inside the stair, though this is not always possible due to the concerns of some code officials.