Do we need both an App and a Component for Lightning Out?

Question

All of the examples for Lightning Out, such as Use Lightning Components in Visualforce Pages shows that we need an app and a component. Is there a way to use just an app or just a component? Ideally, I'd like to just be able to write an App and not need the extra burden of a component as well.

Documented Example

<apex:page>
    <apex:includeLightning />

    <div id="lightning" />

    <script>
        $Lightning.use("c:lcvfTest", function() {
          $Lightning.createComponent("ui:button",
          { label : "Press Me!" },
          "lightning",
          function(cmp) {
            // do some stuff
          });
        });
    </script>
</apex:page>

Ideally, I'd prefer if I could just create the app itself in createComponent or something, so that I don't need to have a small three-line application bundle just for the sake of bootstraping a component.

Answer 1

Yes, the small little Lightning app bundle is needed. Salesforce uses this "dependency app" to bundle all the transitive dependencies of the Lightning components.