Lower peak to average power ratio by phase shifting
Each symbol (in the narrow sense - bit) in your frame modulates a sine wave of frequency depends on symbol's number and phase depends of symbol's value. It can be watched from the Inverse Fourier transform. Then these sin waves are added to each other to create time domain signal. If you change phase relations in your data frame, you change phase relations in sine waves in the sum. By this multiplication you actually do this. So obviously it alter PAPR. OFDM precoding technique (e.g. based on Hadamard orthogonal transform) is an example of using this Fourier property.