Why Do Splash Pages Still Exist?

What’s Wrong With The Splash Page?
Mainly, that ridiculous enter prompt. By going to the site we have already decided to enter the site. Requiring your site visitors to click on an image in order to get to see something is just a waste of their time. Can’t you just assume your site visitors want to see stuff and that is why they have chosen to visit the site? What would be the harm in showing them something without requiring them to perform another action in order to see it? When you open a shop’s front door expecting to see the interior do you think it would it bug you to find instead a door marked enter?