This is actually part of a larger application to control water systems on a truck, so it will be installed in a box on the side of a truck.
The MCP4151 is to drive a Hydraulic Flow Control Valve, which in turn controls the flow of Hydraulic Oil into a Hydraulic Water Pump, thus allowing control of the water pressure out of the sprays.
The idea here is to be able to control it all from a tablet in the cabin, meaning we no longer will need to run 20ish cables into the cabin of the truck, just install a dash mount.