Can't really compare a salary to bounties. With a salary, you can rely on the income.

If you have irregular income, you need to plan for a lot more since you'll always have slow months with no income, or customers that don't pay or pay much later than you expected, and you have a lot of costs that employees don't (eg. you need to pay for your own hardware, office space, accountant, tax advisor, health care, pensions, unemployment insurance, etc).