Some file managers might add the +x automatically if you choose to run the binary through the desktop environment (not the terminal)… or ask you if you’d like to mark the file as an executable (i.e. add +x to permissions).
You can’t do it the same way with tar, what are you gonna execute, tar is neither a script or an ELF binary. It’s like asking for a zip file to be executable, doesn’t make sense. You can change the extension to .exe, but it won’t run, it’s not an exe, no MZ header, nothing 🤷.
One of the few times I've downvoted (sh.itjust.works)