Prebuilt themes are filled with 'coding bloat'; unnecessarily long, slow, and otherwise wasteful resources. Prebuilt themes are meant to be versatile for all businesses across several industries. The issue is,
you're not like all the other businesses. These additional resources and lines of code bog down your website. They are extremely difficult to
optimize for speed, one of Google's most important ranking factors, and are limited to what you can adjust. Prebuilt themes often come equipped with several required plugins, which only increases the chances of encountering incompatibility errors and breaking your website.