Template Website is a website built from pre-designed layouts or themes that are customized rather than fully designed from scratch.
It matters because development decisions affect speed, security, scalability, tracking, SEO, and maintenance. A site that looks good but is fragile or hard to update can quietly hold back every marketing channel.
Example
A new consultancy chooses a theme with an existing services layout, replaces the demo content, and adjusts branding. It still needs to test its actual copy, images, navigation, and forms because a polished demo does not validate the finished site.