[pdw]

It certainly does. There is for example a measurable energy cost for having a blinking cursor in a terminal, and there have been huge flame wars about efforts to move to non-blinking cursors.

The compromise for GNOME Terminal is that the cursor will stop blinking after a terminal has been idle for ten seconds.

[everybodyknows]

Why not similarly disable seconds display after some specifiable time has elapsed since the last key or mouse event? The decimal digits could be replaced with a greyed-out ":--".