A minor rant of mine: I understand a few cases where someone wouldn't smile in their ads.
I saw a friendly guy in California a few years ago who never smiled in his ads and realized upon meeting him that he had healthy, but crooked teeth.
I can understand if your shtick is to be an aggressive, rough, dominant top who advertises that you will "destroy any hole," or BDSM Dungeon Master that smiling might break character.
But providers who advertise pleasure, relaxation and other similar positive experiences are a lot more likely to get my business if they smile in at least one photo.