Most people I speak with are under the incorrect assumption that changing the useragent makes a website think you're another device. In fact, it only fools only the most rudimentary check because many attributes of your browser and system itself are still exposed. For example, I can tell on https://whoer.net that my OS identifies itself as Windows 10.0, that I have certain windows-specific plugins, that my browser is made by Google Inc., my platform is Win32, and more. My canvas data is yet another fingerprint (read about canvas data fingerprinting) which makes it clear that I'm not, for example, on an iPhone. However all of these points of information are provided by the browser, and can be changed - if the browser supports/allows it.
Firefox has a plugin called Random User Agent, which does just that. It modifies many attributes so that remote systems actually think you're using a completely different device. The experience and what they deliver to your device on Twitter, for example, is completely different when you use Random User Agent versus just changing the useragent alone, because all of those other attributes get changed and they have no way to tell that you are not really on an iPhone, for example.
Implementing these capabilities would allow CEF enthusiasts to bypass some of the draconian rules recently put in place to try to force users to only use certain browsers and help restore CEF to its former utility.