Once we use computer in our business, everything like money, staff control etc…can did it automate, just done by the computer, and I am sure that the mistake must be less than doing by staff.
And you also will save time by doing it, for example, if you need to count the money that you earn today, you may do it wrong and slow if you count by an calculator, by if you have a system and just simply type in the information, it will finish in not more than one minute.
And you can employ less staff because the computer will replace some of the staffs, it will lower the cost on employing people. Once your productivity is higher and there are less cost, then you profit must increase.
Although there maybe people who loose their job, but when there are more product that need to sold out, then there will be a job for sales, it will just like a circle. So it doesn't mean that it will be more people unemployed if business using a computer.