One of the most significant questions often asked by the Apple faithful had been whether the Mac OS and iOS would ever be merged. At WWDC Apple executives addressed this exact question and forcefully stated that this would never happen.
However, they went on to say that there is legitimate merit to enable developers by making it easier to bring iOS apps over to macOS for use on a Mac and become part of their continuity story. This means that if you use the new Voice Memo app on the Mac that is also on iOS, whatever you record on the Mac version is also available on the iPhone and iPad instantaneously.