Of course we care about good UI, but this talk was not about UI techniques. It was all about code, so the focus was there. When doing a talk on fundamental code issues or about how to use services such as Azure, there is a benefit to using a very simple app that doesn't get in the way of the main point you are demonstrating. Of course, if you are showing UI techniques you better have a good looking UI, but otherwise, I think it is not required.
Coded UI is a fully supported feature. With the WebDriver becoming a W3C standard, we are actively encouraging customers to use Selenium for web-apps and with the WinAppDriver becoming available for Windows apps, to use Appium for Windows apps. As such, our investments in Coded UI will be selective and limited to supporting customers on any issues they encounter. We will be improving our support for authoring and running WebDriver based Selenium and Appium tests.
WinAppDriver isn't open-sourced itself, though samples / tests (using WinAppDriver) and supplementary tools are and available on our GitHub repo.
To specifically answer your question, WinAppDriver can work with any IDE, whether it's Visual Studio Community/Professional/Enterprise, or whether if it's Eclipse, Python, and so forth.
This is due to WinAppDriver being based on an open standard (Web Driver), and as such the Test Writing part is abstracted away from the Test Runner part (WinAppDriver/Appium server), allowing you to use any language/IDE/platform you want to remotely or locally drive automation on your Windows 10 target device.