How does permanently reducing the number of fat cells benefit you? CoolSculpting

CoolSculpting will permanently remove fat cells from areas of stubborn, exercise-resistant bulges. This is beneficial to you aesthetically because those fat pockets have a relatively larger number of fat cells than adjacent areas,  tend to be genetic and cannot be eliminated any other way. By removing the fat cells and maintaining your weight through diet and exercise, you will be able to keep your newly contoured figure indefinitely.
However, removing the fat cells will not in itself prevent you from gaining weight. As you noted, the remaining fat cells can expand to accommodate extra fat if you are consuming more calories than you are burning. So no, it's not true that individuals with fewer fat cells are less likely to get fat. The only people who are less likely to get fat are those who ensure that they burn as many or more calories than they consume. CoolSculpting can help you achieve your ideal figure, but it does not give you license to overeat. Please find a board-certified dermatologist to evaluate your shape to find out if you are a good candidate for body contouring with CoolSculpting.

This means that in the area that you treat with CoolSculpting you will have lesser ability to gain fat, since there are fewer cells there.  Be sure to discuss your goals and concerns with your board certified plastic surgeon and consider the pros and the cons. Be certain your surgeon is properly certified.  I've attached a link where you can start your search. 

The real benefit in targeted reduction of fat in specific areas is that you can shape the body to give you that hourglass shape for women or a strong V shape in men.  Even if weight is gained down the road, there will be a tendency to maintain an aesthetically desired shape since the fat gain will be stored evenly throughout the remaining fat cells.  Hope that helps!