title: ViewModel vs Activity member variable?
body: <p>Going by this image, the lifecycle of a ViewModel is pretty much like that of an Activity instance, so why not just use an activity instance variable?  Is a ViewModel better because of the automatic call to <code>onClear</code>? Or because it is observable (in which case why not just have observable, normal member variables)? <a href="https://i.stack.imgur.com/6ciIk.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/6ciIk.png" alt="enter image description here" /></a></p>