Why do you need it?
The loss of a spouse or parent can leave dependants with additional issues to cope with other than the emotional. If you are inadequately insured, your dependants may be left with a dramatically reduced household income, which could affect their quality of life. Potentially there may be reduced opportunities for children such as the ability to pay for a university education or difficulties in maintaining mortgage payments on a reduced income.
In the event of your death, a lending institution will not write off your debt. Rather, they will continue to pursue the debt through your dependants and could, ultimately, foreclose on the loan meaning the loss of the family home.