linux – What is the use case of QEMU chardev pty

I’m new to QEMU and playing around with its chardevs. I faced the option called -chardev pty,id=id. So I tried to create a VM with -chardev pty,id=pty0 and got the message.

char device redirected to /dev/pts/9 (label pty0)

So I tried to send some data to it:

root@super-pc:~# cat /dev/pts/9

and didn’t see any output.

What is the use case of this chardev?