Is income source questioned during B1/B2 visa interview?

I have freelance income earned through the internet shown in my past three years’ tax returns.

Will the VO check my bank statement and Income Tax return statements thoroughly and question my source of income before giving me the visa?

Because if so, I would be in trouble as I think online income would be a major negative point when I am trying to prove an intent to return right?

I don’t think it will be a major negative point. They don’t go into details unless they see something out of oridinary. They may ask about your social ties to home country and what your current profession is. Are you self-employed or working for a company?

What’s the purpose of B-1/2 visa?