The ease of use, I can send money to anyone in seconds without having my private keys stored anywhere or being hacked like other wallets do! It's so much easier than sending coins from exchanges for example because you don't have them sitting somewhere safe (in an exchange) waiting until they are transferred out again when it gets too expensive/unprofitable anymore etc..
You know how your bank transfers take days sometimes? Well this takes minutes!! And then there aren´t any fees either which makes everything even more awesome. All transactions go through their servers but if something goes wrong - just contact support directly by emailing keevo@keewoozlecoinservice comand all will be set right within hours usually :) So far nothing bad has happened yet though =). Also very easy integration into web3 platforms such as metamask via browser extensions.