While there is nothing wrong with having the cream float to the top of your milk if you like it that way, the reason why milk is homogenized is mainly due to consumer preference.

Homogenized milk was first introduced into the consumer market in the 1920s, and since then, the demand for the product has increased to the point where almost all of the milk on the market is homogenized. Homogenization does not affect the composition of the milk.

The main advantage to homogenizing milk is that it only changes the size of the fat globules, making them more uniform, and therefore the fat will remain more evenly dispersed throughout the milk. This means the fat will not rise to the top of liquid or cling to the sides of the container.