A quote attributed to Mark Twain says “A photograph is a most important document, and there is nothing more damning to go down to posterity than a silly, foolish smile caught and fixed forever.“
Not sure I would agree with that. Granted there may be a cultural component in the mix somewhere, but as someone who has painted from observation many faces, the fugitive nature of a smile presents almost insurmountable problems. Franz Hals (below) could do it because he painted insanely quickly.
https://www.art-prints-on-demand.com/a/hals-frans/thelaughin...
https://images.prismic.io/barnebys/a671f804-2e03-4541-afa0-9...
https://az333960.vo.msecnd.net/images-9/laughing-boy-frans-h...
They key issue is that a smile involves the eyes as much as the face. This cannot be faked without the frozen effect: example:
https://images7.alphacoders.com/694/694598.jpg
As for photography, the long exposures of early photography made the capture of anything fugitive an impossibility. However, the moment that snapshot photography was invented (Kodaks Box Brownie) smiles were being photographed all the time.