However, a terminal emulator + X11 and so on can eat a bit of a CPU with noisy processes, eg. the output of mpv eats maybe 5-10 %, because it updates every(?) frame, so maximum work for the whole display stack. Getting the terminal emulator out of sight can get a bit more battery life in these cases.

(Somewhat related: If you have infinite scrollback it turns out that /tmp is actually very finite and can be filled by the wrong command with a couple dozen MB/s.)