Because rooting the Galaxy S5 gives more rights to the user, it is possible to do “more” with Android. That term stay on purpose so broad, because root privileges can be used by huge for apps and services. Think of performing a complete backup of applications, including for example, your savegames or other important content. Or the possibility of system apps that you do not actually want to switch off entirely? This feature is especially useful for Android phones with bloatware or unwanted apps from manufacturers.
Ideas are an important option for root privileges is the ability to install alternative kernels. Through a kernel example, you can improve the speed and battery life of your smartphone. Thus it is possible by using an alternative kernel in order to adjust the clock rate of the processor, colors from your screen or the power of the GPU. These are quite technical parts, so it is advisable only to flash a different kernel if you really mind here also. There are several developers who release their kernels for multiple devices and through a root app let flash the kernel. Then it’s a matter of rebooting, and the kernel is installed.