Will CFexpress Type B double slots become popular? : Random thoughts

The only mirrorless cameras with a vertical grip that are equipped with a double CFexpress Type B slot are the Canon EOS R3 and the Nikon Z 9. Most other models have a double slot for both CFexpress Type B and SD UHS-II. The difference between the transfer speed of Type B at over 1700MB/s and UHS-II at about 300MB/s is too large, but there are several reasons for this configuration. One is simply the space factor issue, because the recording media chamber takes up a lot of space for a double CFexpress Type B slot. Mirrorless cameras that do not have a vertical grip do not have the space to accommodate a double Type B slot recording media chamber. Another reason is that CFexpress cards generate a lot of heat because of their fast transfer speed. Therefore, if a double Type B slot is used, the problem of heat dissipation must be addressed. Although the image sensor is one source of heat in mirrorless cameras, the heat generated by the recording media cannot be ignored. For this reason, Sony has adopted a heat dissipation structure for its high-end α1, α7RV, and α7SIII as a double slot for CFexpress Type A/SD UHS-II (α7IV has a double slot for Type A/UHS-II and UHS-II only), and for the genuine Type A card. However, Type A has a transfer speed less than half that of Type B, and the merit of a faster transfer speed is less than that of Type B. In particular, the speed at which the buffer memory is released during continuous shooting is determined by the transfer speed of the recording media (of course, it also depends on the capacity of the buffer memory). In this light, it is interesting to see whether Type B will continue to have a double slot for Type B and UHS-II in the future, or whether the double slot for Type B will be placed in a body that does not have a vertical grip. It is rumored that the Canon EOS R5 Mark II will have a double slot for Type B, but what will happen?