From the front as well as from behind - well, absolutely flat woman. Only one advantage is obvious - well-designed orifices. And of course due to the flat buttocks it's very convenient to pull your partner in the anus, even without bending her over. And I don't see anything else interesting in this lady! The man is basically of age, so probably the determining parameter for him is the age of the woman and the possibility to work her anally!
Sunbathing naked on the terrace, sucking cock is cool for her. Especially since there's always a chance she'll get noticed by other vacationers. There's a chance to get famous and let other studs ride her pussy.