Drupal 8 brings us except Symfony in backend also Twig for frontenders and Views for sitebuilders. Have you every thought about mixing this two parts of Drupal? In most of cases it is better if frontender knows at least basics of Drupal sitebuilding and Views are one of the most important modules for this.
Views is module, which knows probably everyone in Drupal world and honestly I cannot imagine building even simple presentation website without it. It offers you ability to build complex queries and display their results without having any knowledge about databases just through Drupal UI.
Using Twig functions filters in Views
Usecase: You want to display some text all uppercase and you don’t want to do it in CSS.
Drupal 7 solution: You can create field template with correct name, so it will have an effect only on desired field and inside this field template you will use
strtoupper PHP function.
Drupal 8 solution: You will rewrite field with its own value and use
upper Twig filter. It will look this way:
More advanced Twig expressions
Usecase: Show content of field conditionally or conditionally show content one of two fields.
Drupal 7 solution: Preprocessing or some naughty things in templates.
Drupal 8 solution: Use Twig expressions :)
Twig makes frontend development easier. I’m not saying that we should do everything possible only through UI, as I see there many risks related to harder debugging. Practical use on projects will show us the best way.