Metal Performance Shader puzzle in Depth Cloud sample

In the function processLastArData() a command buffer is committed and the output of the last MPS is immediately assigned without issuing a waitUntilCompleted() on the buffer. What am I missing?

https://developer.apple.com/documentation/arkit/environmental_analysis/displaying_a_point_cloud_using_scene_depth?language=objc

Metal Performance Shader puzzle in Depth Cloud sample
 
 
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