Decent or not, it has one and if the command is scripted into his script, a user doesn't have to figure it out.
Still, like I mentioned, the person doing the compression can also use command line on winrar/winzip to compress file(s) into a self-extracting exe and then the receiver can simply /run it. And, if there's an issue with not wanting to send exe files because some people block them, you can have the sender rename the file to some other extension and the receiver can rename it to exe and then run it.
Example:
User 1: /run rar as files.ext outputfile.exe
*Note that I am not positive on the "s" switch for creating SFX.
User 1 then sends the file to User 2
User 2: /run outputfile.exe
Done.
