The font size of a city name is a visual cue used by Google Maps to indicate its population. The font sizes of city names around the world are not fixed as constant by Google Maps, they are variable, but they are always used as visual indices to indicate the populations of cities compared to neighboring cities in a user-friendly way.
The current population of the Hong Kong Special Administrative Region (SAR) in the People's Republic of China is 7,475,170, based on Worldometer's latest United Nations data and the current population of Macao's SAR is 646,141 inhabitants. 100% of Hong Kong's population is urban. Worldomètre