Is it worth to delete temporary & prefetch files?

Temporary & prefetch files are generated by our running programs, Each and every program creates their own temporary and prefetch files folders,folders. now the question is this should we delete these files and folders? If yes then, why? And if no, then why we should not?
Before everything ,first of all we need to know what these files are?

Temporary

Windows Temporary files are created by the operating system during the normal course of its running when there may not be enough memory allocated for the task. Windows and Windows applications create temporary files as they run. Working programs store bits of data in files called temporary or temp files. 

Prefetch

Each time you turn on your computer, Windows keeps track of the way your computer starts and which programs you commonly open.Windows saves this information as a number of small files in the prefetch folder. The next time you turn on your computer, Windows refers to these files to help speed the start process.The prefetch folder is a subfolder of the Windows system folder.

If you don’t run a program, Windows does not access the Prefetch information.

And now if we discuss about deleting those files then........

Temporary files are also created for backup purpose by program so these files can be erased when they are no longer needed.Prefetch folder is self maintaining so there is no need to delete it or empty it.If we don't delete it or empty it will automatically erased time by time.

soo, now as conclusion we should delete temporary files but there is no need to delete prefetch folders files.