bonafide11
Worker
As Deggial says: cities are smaller. But also, the speed of conquest is slower in the beginning, and the difference in strength tend to be smaller (if you are playing on a competitive difficulty. Sure, it can help in the beginning too, but the effect is bigger later on.
I still disagree. Unhappiness early on is much more of a hindrance since you have so few cities, they are small, and they need to grow, plus there are so many more ways to control happiness later on in the game than early on. Considering the Huns UU will almost certainly give city attack bonuses early on, it will be easier for them to conquer cities early, and the unhappiness from conquering cities so fast would significantly add up, even if the cities were razed. Razing the cities at twice the speed then makes a significant difference. The Huns will be difficult to slow down early on with these conquering bonuses.