setting the baudrate higher means less time spend on communicating and more time on measurements/math. 115200 is 12x faster than 9600
Communicating a string of 6 measurements, lets say 30 bytes including spaces and \n takes approx:
@115200: 3 msec
@9600: 30 msec
analogReads take approx 0.1 msec lets say including all math 1 usec so lets say 6 channels take 6 msec.
1 set of measurements
@115200: 9 msec => 111/sec
@9600: 36 msec => 27 /sec
So in the end the higher speed serial allows me to take 4x as much samples.
Instead of more samples I can use the extra time to do additional math e.g. averaging and keep minimum/maximum per channel.
Although the IDE serial monitor does not support it, the Arduino can send data as fast as 500,000 Baud. The effect is that you can go up to ~150/second.