I did many things for my customer , made a lot of ad campaigns , did a lot of tracking, suggested him products, kept track of a lot of variables of business, helped him in improving habit , helped him in hiring as well.
None of the work was as effective in increasing his numbers as giving suggestion about the right product.
One right products added more 30% of his revenue, then it struck me - the biggest utility of data science is to select the right product + help us in moving right direction.
Data tell us whether we are doing it right or not.