While the command line is an awesome part of what you can do with most Linux-based operating systems, it’s not necessary to know anything about it to use and love a Linux-based OS.
Android is based on the Linux kernel, has billions of users around the world, and does not expose the command line.
Chrome OS is a popular Linux-based OS that does not expose a terminal.
elementary OS is designed to get out of the way for both experienced Linux users and users coming from other operating systems who have never seen a command line; and it’s loved by both.
Technically, the command line most used in Linux-based OSes is not even implemented by Linux itself, but by GNU Bash and Coreutils. Not every distribution of Linux comes with or makes these accessible.