Yes, Joomla will be still relevant, being ranked 4th most widely deployed CMS platform. However, it is an increasingly competitive market with WordPress dominating the lions' share of the industry.
Upload the Template via the Extension Manager website and go to System -> Extensions under the Manage section. Click Extensions. On the page that opens click the green Or browse for file button and find the file for the template you downloaded on your local computer.
Both are built on PHP, but Joomla users (especially developers) have a much more traditional foundation in that Joomla can be used out of the box with straight HTML, CSS, JavaScript, and PHP without having to learn the “WordPress way” of doing things.
Joomla makes a good option for a blog, a community website or intranet, and for designing an eCommerce platform. It is also multilingual, supporting 75 languages.
Joomla is a great choice for websites that need frequent updates. The user-friendly interface makes it easy to create, edit, and organize content. User-Friendly Interface: Joomla is also known for its simple and easy-to-use interface.