1.Wide range of functions
Many free themes don’t have the mentioned features. At some point you may be required to upgrade to a premium version to access important functions like AdSense support, Footer customization, custom logo and many more. While premium themes come with all these functions in place, you have full control on what to choose from a wide range of available features.
Many paid WordPress themes come with guaranteed support. The theme developers are concerned and want to support their paying customers. Most developers require one to be a paying customer before even signing up on their forums.
Though premium theme can be sold to many different people, they are not as much as the free ones which everyone can afford. This brings in a situation where many sites look similar. To avoid this, one can buy a premium theme and customize it beyond recognition to maintain originality.
Many developers like Theme Fusion have done a lot of effort to create Avada, one of the best selling, simple and fully customizable multipurpose WordPress themes.