If a major illness happens you'd deplete family assets until government and charitable assistance kicks in. Now let's apply that knowledge to Tammy's question. She and her husband have both been getting extra coverage for the rest of the family. In effect everyone is covered twice. Yes, unless there's a specific reason to want the extra coverage it is a waste of money.
Tammy recognizes that.
Let's see if we can explain why it's true. Consider what happens. Each policy has a deductible. That's an expense level that you have to meet before the insurance company pays anything. Tammy will also find that one insurance carrier is the primary insurer and the other is the secondary.