Anything that runs on the Windows desktop uses Win32 at some point in its stack. If you work on anything that is close to Win32 then you may also need to work with Win32 itself.

For example if you work on a game engine or toolset then you must know Win32 - especially if you work on the tools, even if you are using a wrapper like wxWidgets or Qt.

The only time where you can avoid Win32 is if you're using something that completely abstracts away the entire system, like Java Swing or a web browser.