Vue.js $refs usage case explanation

<div id="app">
    <component-father ref="outsideComponentRef"></component-father>
</div>

<script>
    var refoutsidecomponentTem = {
        template: "<div class='childComp'><h5>{{test}}</h5></div>",
        data(){
            return {
                test:'I am a child component'
            }
        }
    };

    new Vue({
        el: "#app",
        components:
            "component-father": refoutsidecomponentTem
        },
        mounted:function () {
            console.log(this); // #app vue instance console.log(this.$refs.outsideComponentRef); // VueComponent vue instance console.log(this.$refs.outsideComponentRef.test); // 'I am a child component'
        }
    });
</script>

<div id="app">
    <component-father></component-father>
    <p ref="outsideComponentRef">p tag</p>
</div>

<script>
    var refoutsidecomponentTem = {
        template: "<div class='childComp'><h5>{{test}}</h5></div>",
        data(){
            return {
                test:'I am a child component'
            }
        }
    };

    new Vue({
        el: "#app",
        components:
            "component-father": refoutsidecomponentTem
        },
        mounted:function () {                
            console.log(this.$refs.outsideComponentRef); // Returns "<p>p标签</p>" object}
    });
</script>