Some organisations believe that their employees should dress smartly. Others value quality of work above appearance.
There are some associations crucially think that their workers should wear formal clothes. However, a few companies prefer working performance of the staff rather than focus on the appearance. While dressing smartly maybe effective, i think there are still better ways.
Firstly, many organisasions have a principle that their employees have to wear uniform. They think that by wearing formal outfit, other people will have strong attraction with the way their work. In the places like hospitals, police office, banks,... where the staff are required to wear uniform for not only to look more polite but easily to be recognized by people or costumers, so that, the costumers could feel much more pleasure and respected. Besides that, jobs such as lawyer, police, doctor, office workers,.. definitely should dress up well to show the professional indication of them. In addition, people can see which organisations are the employees work for.
On the other hand, some workplaces do not require their staff to dress any kind of gown, they only care about the effective performance of the workers. In most of these places, the staff are often not too worried about their outside appearance, so that they can totally concentrate on their work to create more value. Beside that, the members may feel more convenient and comfortable to boost up their effective creativities. For example, the staff who do not usually need to contact face-to-face with the costumers such as online designers, computer engineer...
In conclusion, in my opinion, dressing up would be more formal and proffessional for the employees working in some organisation that need to impress the costumers. Wherares, the workers do not often meet the costumers should wear whatever they feel comfortable and suitable the most to develope their valuable performance.