Whether the payment is "superfluous" is not the point, Fred.
Many pensioners living in the UK do not "need" the Winter Fuel Allowance (i.e. they will not suffer freezing conditions should they not receive it) and so, for them, it may appear to be superfluous. However, it is considered part of the State pension package and is not (for the moment anyway) subject to a means test or a test to see if it is needed or not.
Most recipients have paid quite high (compulsory) contributions for their State pension and indeed many of them would have received better returns had they been allowed to keep their contributions and invested them themselves. There is no earthly reason why their pension package should be influenced by their choice of residence in their retirement. There is already a restriction on people receiving cost fo living increments if they choose to live in a country which "does not have a reciprocal arrangement with the UK". This is totally unjust and seeks to connect the State pension (for which recipients have paid) too closely with State benefits (which many recipients have not). Any attempt to restrict the Winter Fuel Allowance on the grounds of place of residence would be equally unjust.