Most websites today have an image slider on the home page displaying images and text to try to attract the user's attention. But does this method really work? Many usability tests say no. For example the test described here http://www.nngroup.com/articles/auto-forwarding/ shows that because the slides kept changing automatically the user didn't notice the promotion they were asked to look for.
Another issue with sliders is page speed. Images are usually the largest asset on a web page so when you add a bunch of large images to a slider that can add up very quickly. As a great example our home page on desktop loads at about 500 KB. Out of that 500 144KB of it is the main image. So if that image was in a slider with multiple other images of the same size we would be quickly doubling the loading time.
Responsive sites especially suffer from sliders as the mobile site in most cases will use the slider as well. A slider will make a mobile site load much slower and a fast mobile site is very important for users with slow connections.
Image sliders are still great for showing image galleries and in the past were unique and interesting. But after using them for so long we've learned these issues and know there are many better ways to design a home page. If you still have doubts this site is a great resource: http://shouldiuseacarousel.com/