"As it is now possible to enter directly into an Answer a 'You Tube Link', I feel that the box 'Enter You Tube Link Here' is somewhat surplus to requirements."
It is! At the time of launching the new "automatic embed" system we did consider removing it - but as so many were still using it we thought we'd let both options ride for a bit. This was partly to avoid hundreds of users asking where the box had gone.
It is probably time to reapproach the layout, thanks for the reminder.