If I ever have to use a command line for anything but THE most esoteric, potentially system-damaging scenarios
But you don’t have to though, at least if you’re running a sensible distro and have Linux-friendly hardware. My elderly parents for instance have been running Linux for over a decade now (Xubuntu first, now Zorin) - on bog standard Dell machines - and never once had to touch the command-line. I think I intervened a couple of times a maybe 4 or 5+ years ago, but haven’t had to any major tech support or CLI intervention in the few years.
Linux has come a long way. If you’ve got compatible hardware and don’t have any specific proprietary sofeare requirements (like Adobe etc), then I’d recommend giving it a try. If you’re open-minded that is.