If anyone sent me an .rar these days, it would go straight into the Trash. (Ditto for Koreans who insist on sending me .alz archives.) Sure, 7-Zip can probably open it, but I still prefer .zip which has much better compatibility overall.
I can understand why those who have used WinRAR for many years might keep using the .rar format out of habit even in 2012, but is there any other reason for anyone else to compress new files with .rar at this point? Sure, you might be able to shave a few more kilobytes off a large file, but small differences like that are becoming increasingly irrelevant compared to interoperability. Are there other technical advantages to the .rar format that other formats like .zip and .tar.gz lack?
Encryption that isn't completely useless. Recovery records. Huge file support. Better compression in specialised cases (x86 binary code, multimedia). A nicer GUI - 7zip is a clunky, fugly thing and WinZip... urgh. Garish as Las Vegas. A real x64 version (for no reason other than OCD-ness about mixed 32/64 bit binaries). And tar.gz is grotty for random-access, I-know-it's-in-here-somewhere, use cases.
That said, I do still use zip for compatibility 90% of the time - but I was only going to pay for one commercial archiver for Windows, and WinRar was it. Why pay for WinZip? (this was years ago, amortized cost is now less than pennies/day)
Of course you could ask why pay for software at all, but that's a different problem. I'm happy to pay someone for software that works better, does things that otherwise can't be done or would be tedious, or is a de-facto standard of some sort. Hence at one time or another I've paid for Adobe Creative Suite, Cubase, MS Office, VMWare Workstation, Rhino 3D, Autopano Pro, and others.
multi-volume, robust recovery (up to 20%), built-in solid encryption scheme
Of course in the terminal world you could chain it all. But rar provide a convenient package of it all and with a gui.
Zip files are painful to deal with when the system encoding is different from the one that created the archive.
.zip has the table of contents at the end of the file; .rar has it at the front, so if you've downloaded 50% of a .rar file you can easily get 50% of the content. You can't easily extract a zip file until you've downloaded the entire thing. So if downloading over a slow compression, which does still happen depressingly often, .rar does have a significant advantage over zip at least.
ZIP contains full listing at the end of the file.
Saying this, ZIP also prefixes file data with file header information, allowing to decompress partial zips. ZIP recovery software will use this to recover broken zips.
Why do you think it's stupid? Here are my reasons for the statement you quoted:
1. It's been years since anyone has emailed me an .rar attachment. In fact, I don't think I've had a legitimate .rar file in my Inbox since the turn of the millennium.
2. The last time I regularly opened .rar files was when I was into warez. Those things often contained malware.
3. As a result of 1) and 2), I would be very suspicious if somebody sent me an .rar file.
Of course, that's just my perception, so other people might associate the .rar extension with better things.
I can understand why those who have used WinRAR for many years might keep using the .rar format out of habit even in 2012, but is there any other reason for anyone else to compress new files with .rar at this point? Sure, you might be able to shave a few more kilobytes off a large file, but small differences like that are becoming increasingly irrelevant compared to interoperability. Are there other technical advantages to the .rar format that other formats like .zip and .tar.gz lack?