Describe what you want, not how to do it & rejoice in the increased readability of your code. Code is communication between people, that also happens to run on a computer. If you optimise for reading by humans, then over a long time your project will end up better.
Create re-usable chunks of functionality that can be seamlessly integrated into your reactive pipelines. These chunks might be widely applicable, or specific to your application. Regardless, you have the power to write and test code once, and leverage it many times over.
Any device, any platform. Share business logic between your mobile and desktop applications. ReactiveUI has first class support for Xamarin Forms, Xamarin.iOS, Xamarin.Android, Xamarin.Mac, Tizen, Windows Forms, Windows Presentation Foundation (WPF), & Universal Windows Platform (UWP).