Root-access, or Superuser, comes from the base Android system - Linux. The author's answer is overly sensitive, custom recovery is needed for flashing, and an overclocked kernel (core) for overclocking, root can affect the processor only by changing the maximum and minimum processor frequency (from the available one). They are needed for some points:
editing system resources (uninstalling programs, modifying)
installation of third-party frameworks and their work, a good example of XPosed - it allows you to change the device beyond recognition with the help of modules and improve the functionality.
programs to change application settings, such as hacking games by bypassing Google payments.
The list goes on and on.
root is a modification of the system, foreign software. Many guarantees include a clause prohibiting the installation of foreign software by the type of root or "flashing". Thus, you may lose your warranty
You will lose access to the Android Pay system, which is protected by SafetyNet - a script from Google that blocks access to the same Android Pay when root rights are detected. Pokemon GO even has such a system.
in inept hands, root is a time bomb.
the system is more vulnerable to malware.
Root rights - superuser rights, if you get them, you can personalize your smartphone to the maximum. You will be able to change the firmware, install different applications from "game crackers" to applications for overclocking the processor. But it is worthwhile to think carefully about such a step as getting root rights. Because of the inept Use of programs and utilities, you can "distort" your device. And even after obtaining superuser rights, the guarantee is canceled.