As a long time, .NET developer one of the things, I have loved about XAML is its under-the-covers support for UI Automation through the AutomationProperties https://docs.microsoft.com/en-us/uwp/api/windows.ui.xaml.automation.automationproperties?view=winrt-22000 which in turn provides a ton of basic Accessibility support.

https://docs.microsoft.com/en-us/dotnet/framework/ui-automation/
https://docs.microsoft.com/en-us/windows/win32/winauto/entry-uiauto-win32

Complying with Accessibility requirements like screen reader support and others is quite easy to achieve on many XAML platforms because of these AutomationProperties.
Another beneficial side effect of those properties is the ability to run a variety of off-the-shelf automation test tools against the applications.
Automated testing, and being able to use existing tools that are based on the UI Automation standards would be a very nice to have

Here are just a couple of examples of common tools that are commonly used on many projects that leverage the UI Automation standards and the AutomationProperties:

https://docs.microsoft.com/en-us/windows/win32/winauto/inspect-objects
https://docs.microsoft.com/en-us/windows/win32/winauto/ui-automation-verify

There are other standards that are also potentially relevant like this one for example:

https://docs.microsoft.com/en-us/compliance/regulatory/offering-wcag-2-1

Appium is an open source test automation framework for use with native, hybrid and mobile web apps.
https://appium.io/