These "hardware addressing" pins are not for addressing words in the RAM, but rather to select the address of the whole device on the IIC bus. The manufacturer realizes that you might want to have several of these chips on the same IIC bus, which means they each need a different IIC bus address. These pins allow you to pick one of 8 pre-defined addresses for each chip, depending on whether you tie these address lines high or low.
Some devices just use high and low on the address select pins. Other devices use high, low and open for trinary logic. 3 pins would give you 27 address possibilities. The TI INA219 only has two address select pins, but it uses 4-nary logic with high, low, connected to SDA or connected to SCL for a total of 16 address possibilities.
