It gets the pin number needed to make changes in the CEM. Like software reloads, cloning ... ect.
Yagger can get the PIN through the OBDII port but like all the other services the CEM PIN is not shared with the customer. It is used by him to provide his services. VDASH does the same and it makes sense. If they gave out the CEM PIN. Idiots would messing with things and then try to blame the service provider in order to get their mess fixed for free. Fixing someone else's mess is not cheap.
If i recall correctly Yagger's method for the P2 requires hardware other than DiCE. Or like VDASH you can snail mail the CEM and he will put the CEM pin on file in your account information.