QQmlApplicationEngine is a class from the Qt Toolkit which provides a convenient way to load an application from a single QML file.
In the QT framework, the QQuickView class provides a window for displaying a Qt Quick user interface.
Headline newer powerful
"Since qqmlapplicationengine is newer than qquickview one would naturally assume that it is more powerful"
from question "X11VNC performance - QQuickView vs QQmlApplicationEngine"
"Headline qqmlapplicationengine is newer and more powerful than qquickview"
from question "What is the difference between QQmlApplicationEngine and QQuickView?"