To play devil's advocate, you can argue that a disadvantage of a nationally homogenized culture is the loss of innovation; when all tastes are similar, fewer people will be creating new things. Think about the common admonition to "Try something new!" In a homogenized culture, there would be very few "new" things to try, and so it is possible the culture would stagnate.
On the other hand, if there is a proper process for vetting safety and effectiveness, many products will end up being the pinnacle of their type. By constantly refining the things people like to be better, we end up with superior products.
You would be able to maximise production and sale on products that are going to be bought in great numbers by your consumers. Clearly having a globally homogenised market would mean that you can predict tastes and supply to that demand, maximising income.
Imagine how much easier it is to market and sell products to only one culture. You could focus your advertising dollars around one campaign and only have to worry about one set of themes and one method of delivery, not to mention only one kind of cultural sensitivity. It would save a bunch of money.
A homogenized culture also brings economies of scale to production. If "one size fits all," whether literally or figuratively, manufacturing is simplified and streamlined. Mass production generally means less cost per unit. This is also likely to be true of services, since there are fewer ways in which service needs to be diversified.
Homogenization makes it easier to sell products, because everyone has the same culture and consumes the same goods and services in the same way. Globally, this is unrealistic because there are so many different cultures. However there is some amount of homogenization as more and more countries adopt Western culture and consumer ways.
The advantages of such homogenization come from the fact that, in each case, the homogeniztion creates a larger market to which a firm might sell.
When a country, or indeed the world, becomes more homogenized in cultural terms, certain firms see their potential market expand. When a culture is fragmented, a movie firm, for example, can only sell a particular film in one area because it will not translate well to other cultures. As the nation or the world becomes more homogeneous, the film becomes saleable in more areas. The same might go for clothing or for food and drink. The more the whole country or the whole world shares one culture, the more various kinds of clothing, food, and drink can be sold everywhere.
In short then, a homogeneous culture means a larger market for products whose popularity depends on the tastes of the consumers.