A Macbook Pro (or indeed any laptop) battery operates at a voltage much higher than that of your phone or a powerbank. The actual power available from the battery (in Wh) can therefore only be compared with another battery's quoted capacity if the voltage is taken into account.
A MBP battery might be a 11.1V battery, while a portable power bank capacity is almost certainly quoted as a summation of the capacities of the 3.7V cells inside. The capacity of the power bank must therefore be divided by 3 to give the equivalent capacity in mAh at 11.1V.
A MBP battery might be a 11.1V battery, while a portable power bank capacity is almost certainly quoted as a summation of the capacities of the 3.7V cells inside. The capacity of the power bank must therefore be divided by 3 to give the equivalent capacity in mAh at 11.1V.