Apples and Oranges-- the 2 systems are both valid within their context.
if taught correctly, the american style has much to offer . You need to remember WHERE this system originated , and for whom it was designed. It essentially, has been around since the twenties ( up dated. of course ) It also provides coaching from world class dancers , and has produced many world class Prof. competitors in both Standard and Latin .
The system was , and is,beneficial to those who do not wish to pursue, a very strict form of social dancing, but are there more for the fun. But, if you so wish, the upper levels are available, in many schools .