The apps everywhere nowadays are all dynamic websites. Almost everywhere are the interactive dynamic websites rather than the static ones that may be compared to a catalogue. No changes could come about in that catalogue unless the structure was changed. If comments may be typed or payments made, it is a dynamic website for sure like the ones by WordPress. Too many of those dynamic websites exist, like the pebbles on the beach.
The software giants like WordPress provide website building facilities for free. Innumerable websites have been easily created with the help of the software facility. What purpose do they serve? Ecommerce sites earn billions besides blogs and social media sites, and all of them undergo regular updates. Static websites allow no such updates.
Dynamic sites usually need a content management system or CMS. A coding language like PHP is needed to work with databases. Webhosting facilities would be required and servers too. Now it is understood why dynamic websites are costlier and more difficult to construct.
CRUD represents well the characteristics of a dynamic website where the software allows you to create and read, update and delete. The database functions that way. That is what happens in a blog, for instance. Social media sites allow typing and editing, deletion too.
We design dynamic websites all the time and an immense variety of formats is available. Interactivity is important and users can do many things out there. Leave the technical aspects to us and decide about the required functions.