Over many years as a financial adviser Chris has come across clients that have lost a loved one they were financially dependent upon, some of whom have had provision in place and some of whom have not.
No amount of money can ever compensate for the emotional impact of that kind of event, but not having to worry about paying the mortgage, or not being forced to downsize and move (effectively putting one very stressful event straight after another) can at least lessen the anxiety and allow people to grieve in their own time.
Naturally the most obvious things to cover are mortgages and other debts and replacing lost income while children are growing up and still dependent. This need not be expensive and premiums can be guaranteed not to increase once in place.