Like most things, it depends.
Mortgage Protection is required by law - so by and large (there are exceptions) if you buy a domestic house (not an investment property) you will take out life cover to pay off the mortgage in the event of your death during the course of the mortgage. It means that your dependents/estate will not be carrying a debt.
It is possible also to buy additional cover to deal with illness or chronic disease but that would be above and beyond life cover.
mf