Don’t you want to replace the radiators with large vertical floor to ceiling radiators to get the same amount of heat transfer at a lowest possible temperature?

Don’t you want to replace the radiators with large vertical floor to ceiling radiators to get the same amount of heat transfer at a lowest possible temperature? I am not familiar with the nuances, but this appears to be an equation with two variables - water temperature and radiator surface area. Maximising surface area should slow you to use lower water temperature. And the lower the water temperature, the more efficient the heat pump will be?