I don't get the point of everyone worrying about cleaning the wheels.
Besides being a concept, those wheels will be on a car wit Carbon Ceramics and there is no brake dust. At all.
The only delicate part I can see is the coating of the CF barrel, otherwise just power wash and air dry
In regards to the practicality, HRE obviously choose a design that shows off a structure that can't be machined. One of the cool benefits of printing...