Dynamic Websites are for people that need app like functionality on their website. Want to build a forum of FAQ? Need a live search? Want chat like features? These types of things are not Static and need to be changed by the second. This sometimes can come at the expense of speed which is why Static Websites can be faster. However depending on what you need it for the trade off can be more than worth it. For content that does not change so often I suggest looking into using a Content Management System combined with a Static Website.
- Do you want to not worry about managing your site?
- Do you want amazing performance and speed?
- Do you want great animations?
- Do you want to something a little extra with search, login, or other app like functionality?