I have never by choice used rar /or/ 7z. I'm not a heavy user of compression, just the occasional "compress for transport", so to me any savings in file size is an unnoticable rounding error, even 15 years ago. Far more important to me is the simplicity of having tools for compression/decompression built into pretty much any computer that might receive my file, and where the receiver of the file, who may not be technologically adept, knows what it is without me having to explain that it is a compressed file and they neeed to get some tool to decompress it.