It's not limited to Windows 7 era GUIs by design, there are plans to have GUI support for OSX, Linux, Android, etc...
Furthermore, don't get confused between styling and layout. The code is focused on layout, the styling can look just as modern as any other GUI framework.
Lastly, as to why anyone would use Red, it enables you to create full graphical apps in a small amount of code, and is designed to be compact (runtime under 1MB) and fast (native compilation). Once you get familiar with the syntax (which is easily done by reading a short tutorial) then you have quite a powerful tool at your disposal.
Furthermore, don't get confused between styling and layout. The code is focused on layout, the styling can look just as modern as any other GUI framework.
Lastly, as to why anyone would use Red, it enables you to create full graphical apps in a small amount of code, and is designed to be compact (runtime under 1MB) and fast (native compilation). Once you get familiar with the syntax (which is easily done by reading a short tutorial) then you have quite a powerful tool at your disposal.