There was no skin tight bodysuit and gyrating when Whitney Houston ‘sang’ the Star Spangled Banner while a studio recording of her singing played.
https://en.m.wikipedia.org/wiki/The_Star_Spangled_Banner_(Whitney_Houston_recording)
So, even the great Whitney Houston used the lip synch technique?! I’m no singer, but maybe the quality of a pro’s voice varies by the day. Maybe she wanted to be sure she didn’t have sinus trouble on the big day.