Runs down the (much) lower amp hour, smaller capacity racing batteries way too quickly, especially if it is for more than a few minutes.
It becomes more of an issue when one lives in a colder climate, and needs every one of those cold cranking amps in the winter, along with the added detriment of not being able to charge the battery in the car with a charger, due to living in an apartment.
How cold does it get there in winter, in your part of Oz?