What have suppose to using laravel yield() function?

main page -> welcome.blade.php

@extends('layouts.footer_back_to_top')
@section('footer_back_to_top')

@endsection()

footer page -> footer_back_to_top.blade.php

<p id="back-top">
    <a href="#top"><span></span> Back to Top</a>
</p>
@yield('footer_back_to_top')

The question I want to ask is without using @yield('footer_back_to_top') still will display the result?

via Chebli Mohamed