Summary
The way you store and retrieve structured data in an Android application has a direct knock-on-effect on how your user will experience your application. When you choose to use a system like Room, CouchDB, or Firebase, where data changes are pushed through the application as updates, the user will naturally have a reactive application. What's more, the application will generally be responsive because these patterns naturally keep slow running queries and updates off the application main thread.
Room provides an excellent addition to the standard Android data storage ecosystem, not only dramatically reducing the need to write boilerplate data access code, but also providing a well-defined and excellently-written interface to run reactive queries for data. Of course, not all of your application needs to be reactive; once an object is delivered via a LiveData object, it's just an object and can be used as an in-memory snapshot or even edited if it's mutable.
When using Room, it's important...