Did you know that if you have draft beer taps, you will be forced to throw away some amount of beer daily?
One to Two pints of beer get stuck in the pipes that run from the keg daily. The beer gets spoiled overnight since the flexible pipes do not have special cooling system. You will have to throw it away every morning before refilling the pipes with fresh beer for sale. What happens if you don't sell enough? You will end up loosing up to 20-25 litres of beer monthly.
In case your daily sales are over 20 litres for each beer, (40 pints or more), the lose might be insignificant, but in case you don't sell enough beer (due to some reasons -maybe your guests prefer wine or the culture is not really "a drinking one") you loose a lot every month. So it might be better for you to stick with bottled beer.
* Actually, there are special cooling systems for the pipes (which might not be affordable for you). Not only for saving beer, but to also make it cooler, especially during hot sunny days.