Erich J. Schultheis wrote:

plug in a TV to the cable box and use the cable box to control current
to the TV?

I know is probably there for older TVS but what about newer TVs with
more complex circuitry?

Could I possibly damage anything within the TV but suddenly cutting off
the electricity with the cable box?

I think it saves wear and tear on the SMPS, and adds convinience if the
set turns on when plugged in, like a sony that's been unplugged when on.
If you need to press the power button after plugging in, then it's just
an extra step.