Life insurance is INCOME tax-free. Life insurance proceeds are not exempt on the Estate tax side; unless you use an ILIT. I know that we are talking about FE policies and for the most part low income people, but LIFE INSURANCE IS NOT ALWAYS EXEMPT FROM THE ESTATE, therefore subject to estate taxes, providing the estate exceeds 3.5 mil.......
Just remember also that most of the time with FE you're not going to make the beneficiary "To the Estate of" anyway. There will be another person who is not part of the estate recieving the death benefit. So it won't be going throught the estate or probate at all.