Apache has been the de facto standard web server for over a decade, but recent years have brought us web servers that consume less RAM and handle many more requests per second using fewer threads and asynchronous i/o. In my opinion, I also find the configuration of these servers to be more straightforward and minimal.
Why do people use Apache when asynchronous servers are so much more lightweight? Is there any clear benefit?
Apache's .htaccess provides flexible configuration. This allows users on a shared host to customize certain settings of an apache without having to alter the core apache configs.
It is the standard server bundled in typical LAMP setups, although, many services use other web servers for in conjunction (like static files, video streaming, etc.).
Since Apache is popular, it's easy to find a solution to any problems.
Other than that, other solutions would probably be better.