Not everybody agree on how it should be classified: .38 S&W variant or a unique case type? One one hand, the .38 S&W has different case dimensions and is not just a shortened .38 S&W Special, and on the other hand, CBC and other companies have manufactured cartridges having dimensions that do not always agree with CIP or SAAMI standards (for example, CBC also manufactured a .38 Short Colt based on a shortened .38 S&W Special case).
However, since CBC have manufactured both the .38 S&W and the .38 S&W Special Short at the same time, there is no doubt that it was intentionally made as a .38 caliber cartridge with improved ballistics that is able to be safely used in a variety of guns chambered for short .38 caliber case types. So in my opinion I agree with John, it should be considered a distinct case type, but not forgetting that there are no firearms specifically chambered for it.
As a side note, some confusion can be caused by early CBC catalogs, because the .38 S&W is listed as the “.38 S&W Curto”, although they are referring to the regular .38 S&W case type. Its description says that it was intended for guns chambered for the .38 S&W, .38 Colt Police Positive/New Police and also No. Mk. I revolvers.