as the other person mentions, the purpose of camm standard is speed. sodimm has realistically hit its frequency limit, which is why the lpddr versions of devices tend to have higher clocks. the faatest components in terms of bandwith is always the closest to the cpu sock (which is why for instance, the fastest pci-e lane on a motherboard is usually the top most x16 slot, as well as usually fastest m.2 slot).
camm is the fix required for next generation high speed memory because of the phenomena, else igpu performance is going to be held back, which doesnt bode well when igpus are getting bigger to able to take a load off AI workloads.