i thought the whole point was that they are considered to be one and the same - since the council of Nicaea in the 300s AD.
I guess they didn't want to return to a pantheon of gods as they had previously In much of the region l, as this tends to dilute the power wielded by the religious organisation, but they also needed to bring in their guy as a god to provide a clear distance from Judaism, so this particular bit of mental gymnastics was employed