Every business decision is a cost-benefit analysis whether you're doing the actual calculations or not. From an email you answer immediately or let sit to hiring to choosing how your website is built.
We'll explain in terms of using Wordpress, but the principles are true of any content management system. Even though Wordpress themes are not templates in the traditional sense, the end-product can certainly feel that way after being set up.
There's no realistic scenario where a developer would start from scratch on a website and if someone says that he or she needs to then you're dealing with an inexperienced developer. Custom designs should always begin with at least a framework.
Websites are an extension of your branding and in many cases serve as merely an online brochure with a contact form. From a functionality stand point there isn't much to it. There are a couple website business objectives that can be met with templated websites.
Marketing and ad campaigns always need a location to convert potential customers and template solutions like EXAMPLE can be an excellent option.
Depending on how you're planning on
As the center piece of your brand or marketing campaign the decision of your website construction is an important one, but doesn't have to be a difficult one.