Have a look at all of the popular open source home automation solutions out there and you will find the following: they all provide a good level of integration with a wide range of devices, they all provide a method to automate - usually via rules or scripts and they all provide a user interface. These three functions vary considerably; some will limit the range of devices, some will need you to learn to code the automation and many will have you spend countless hours just to get a widget to actually look like the dial on your heating controls.
Of course they all do these to varying degrees. In most cases nymea will integrate a commonly used device, automate it quickly without coding and there is no messing about with an interface; it is what it is, simple, effective, clean and pleasing on the eye. I have spent a lot of time studying the top open source solutions and am often ‘blown away’ just how easy it is to get nymea to do some of the complicated stuff in minutes not days!