Actually, the couple gets less per month if they choose to have the pension set up with survivor benefits. This is because the level of benefit, is calculated on the probability of the beneficiaries to live a number of months. So the probabilities are pretty simple to figure, and if two people are on the program it will run . The payment amounts are set so that the total payout will be same irrespective of which choice the couple makes.
If you don’t have the survivor benefit, and you die, then the other half of the couple gets nothing.
My father survived ten years after he retired. Mom made it another 18-years. If they had chosen to not establish her as the survivor, and take a bit less money she would have been living with one of us kids for those 18-years. Because she would barely had enough to feed herself Based just on her contribution to Social Security.
And statistically most people or couples get more back from Social Security than they put in. So, if they elect a plan which includes a survivor benefit or not, typically if most people were living off their own investments they would run out of money before they die.