When a graphic user interface is web-based it is called WUI (a Web-based User Interface), and this comprehends most common websites. Most websites are now controlled by outside programs, and the GUI is much more flexible than in a classical web-browser based on HTML.
When trying to create happy computer users, most experts agree that the user interface is probably the most critical element. The person's psychology must be taken into account, in addition to learned biases, abilities, and the fact that each of us has exactly two hands. The GUI must take all this into consideration in order to best serve the purpose for which it was intended.
Binary options trading, a new but quickly growing field must take this into account very strongly. Since it is entirely web-based, the GUI is very important.
Unlike traditional trading, the user never actually buys an asset. Take the example of binary stock options: Rather than own an actual share in a given company, the trader is only predicting whether the share price of that company's stock will rise or fall within a given time period. If he is correct, he profits, and if not, he loses. Therefore binary options are often referred to as cash-or-nothing options.
This system is very simple and accessible when held up against traditional financial trading. It is especially good for beginners because the risk is predetermined and you know what you're getting into. It is a very short-term style of investing and after picking an asset, you only predict if the price will rise or fall.
For this reason, binary options platforms must have a strong user interface. The best part about binary options is that they are simple and straightforward, and the user interface must keep that up. It must be simple to grasp straight away and simple to master.
Most binary options platforms build their GUI such that the trader just needs to use one button to activate a trade. There are also other ways to encourage simplicity though by using clear signals such as colors and universally recognized icons.