The Selenium Java bindings are moving to a model where we use *Options classes, rather than straight DesiredCapabilities. For example, Chrome can be configured like so:
ChromeOptions options = new ChromeOptions();
options.setCapability("platform", "Windows 10");
WebDriver driver = new RemoteWebDriver(options);
This is to remove a class of problems caused by people putting items not meant for (eg) Chrome into the chrome config (things like a firefox profile, for example).
The Platform Configurator encourages people to use DesiredCapabilities instead, which perpetuates the older way of doing things leading to problems as we move inexorably towards a w3c future.