Not sure how this

    {isVisible && <div>Hello World</div>}

is uglier than

    <div ng-if="isVisible">Hello World</div>

or

    <div v-if="isVisible">Hello World</div>

or

    {{#if isVisible}}
        <div>Hello World</div>
    {{/if}}

Plus, isVisible in React is not a string but a variable, so you can use Rename Symbol and Find All References on it, inspect its value in your browser's debugger, inspect its type if you are using TS or Flow, and so on.