The site is meant for people who use up all their CPU and need to do a transaction. If you wait for a 1-3 days your CPU will regenerate. Similar to like how your voting power on steemit regenerates over time. The site is great for those who are using DApps on EOS blockchain that run out of CPU because of many transaction eg. dice rolling games but can apply to other games not just betting games. Bascially the site is delegating EOS for you to have CPU and then they will undelegate. Similar to how users on steemit can delegate Steem Power to any user and then take it back when then want.