You have zeroed in on two of the features the SpyderCUBE offers that flat targets cannot. A third feature is data on primary and secondary light sources. Another unique application of SpyderCUBE is to record information on light source locations (to reconfigure lighting later for SGI configuration). So, while the SpyderCHECKR 24 will provide averaged frontal lighting information for gray balance and color calibration, a flat target will not provide the types of special data offered by the SpyderCUBE.