Why in steam turbine maintain steam temp 535 degree Celsius?

IT is not accurately 535 c.... The water should be in the super heated condition... So we go to like a higher temperature region and also higher pressure region to change the steam as super heated steam and then the steam is allowed to expand in the steam turbine... now the power gained is much higher than the water flowes at saturated condition like (200 c - 300 c )... so only we are moving to higher temperature and higher pressure region