rar files

Question

What is the advantage of rar files? Zip files are supported by current versions of Windows and are easier for me at least to use. Why do others use rar format? I am posting this question here because as far as I know, there is no advantage to allowing rar format files.
 
Related to this, some of the articles have sample code in rar files yet the download filename has the zip extension. I see no value in doing that; I think files should have the correct extension for the format that the data in the file is. In other words, if I download the file, it has the zip extension and then Windows can't open it. If I rename the extension to rar then I can open the file using the utility that I have for rar files. I think the extension on the file should be zip, not rar, since it is a zip file.