The total costs of these 'benefits' is less than £6 billion p.a. This is less than 0.75% of government income, lees than half of that spent on overseas aid for such things as pop bands. Given the wastage and mismanagement of money by all governments this is a negligible amount and does make a needed and welcome difference to the living standards of many pensioners.
If you really believe that this money would and could be better spent elsewhere, you have more faith in politicians than I do.
This suggestion smacks more of political games to maintain the impression that those who have contributed all their working lives are somehow getting something for nothing and living high on the hog, rather than receiving one of the worst pensions in the world and often having to struggle to pay bills.