Like when you send a .7z instead of a .zip or .rar to a friend or a teacher because that’s what your computer has installed and they’re like “Oh No, not one of those, now I have to install 7Zip” even though the same program that opens .rar also opens .7z I feel like people are way more annoyed when they receive a .7z
Unix (including Linux and BSD) tend to prefer tar. I have seen many Unix systems without zip support, but have yet to find one that does not have tar, even imbedded systems with just a few megs of disc and ram have tar
If they choose to use some obscure Unix system as their daily driver then it’s on them. Unless they specifically request tar or some other format, go with the safest option, which is zip.
People who are using Unix based systems know how to install a zip utility if their OS doesn’t natively support it (most do) and can do so in seconds.