A web host is the company that owns the physical space on the internet (the web server) where your website exists. This is where files (web pages, images, audio and video etc.) are uploaded to and downloaded from.
We can, and do, use other cheaper web hosts but they’re just not in the same league!
Cloud hosting, in this case, refers to an array of servers all sharing the load of your web site/service. With this model, downtime is limited and you increase the speed, reliability and accessibility of your website. Traditional hosting solutions require that you share a single server with many other websites. This, especially at peak times of day, can often lead to slow page load times and even the unavailability of your web pages.
…when a site responds slowly, visitors spend less time there – Google Webmaster Central Blog.
This is also an issue that Google now take into account, so faster page loading will also increase your chances of ranking highly in the Google’s search engines.