Is just another way to do web-hosting, your concern is more related to cloud solutions applied to shared web hosting, in that case, these providers are just using the benefits of the cloud computing on the web hosting A good example, is Cloudweb, which is a very reputable and recommended company!
█ Whitesystem.NET,INC.root [at] whitesystem.net
█ Native SSDTrue CLOUD cPanel-based Shared, Reseller (root access!) Hosting.
█ LiteSpeed • Low Populated Servers • 7 Years Hosting Experience
█ Fast and Friendly multilingual (Spanish and English) Support www.whitesystem.net
Cloud Hosting allows customers powerful, scalable and reliable hosting based on clustered load-balanced servers and utility billing. Removing single-point of failures and allowing customers to pay for only what they use versus what they could use.