In many cities, urban planers tend to group shops, schools, working facilities and homes in specific areas. Although having similar facilities grouped in one place may provide sense of diversity, I believe, that such arrangements have more disadvantages than advantages for many reasons.
In terms of the benefits, infrastructures grouped together may be convenient because people have different options to choose from in one place. Having a choice and diversity is convenient because it allows to view different options in a short time, without having to drive in different locations. For instance, shopping malls are a perfect example of shops located in the same building.
However, these infrastructures can be inconvenient for business. Having many different facilities for similar purposes may create a high competition between the shops or schools. That may lead to fail for some companies. For instance, there are several grocery shops located at the same place, one is owned by a bigger corporation, has cheaper prices and has a larger area. Chances are that most of the customers would make their shopping in the first one, rather than in the second one. This would lead to decrease in sales and over time, it may lead to bankruptcy.
Furthermore, I think that mixed-use development provides more benefits. For citizens, it is more comfortable to have several different facilities near their home , than a group of specific ones only. For instance, some people leave far away from the supermarkets, but they live near clothing shops. Food is a basic necessity for humans, meanwhile, clothing is bought rarer. This is why, this type of arrangement is not convenient for everyone.
In conclusion, this type of planning provides diversity in one place, nevertheless, has its own disadvantages in case of business and location. In my opinion, disadvantages outweigh the advantages and mixed-use urban planning is a better option.