What is the deal with these new cloud/Saa services? Convenience over installing your own server and managing your own data? Outsource it to parse.com? How can

What is the deal with these new cloud/Saa services? Convenience over installing your own server and managing your own data? Outsource it to parse.com? How can you be certain your data wont be compromised, read or misused by parse.com or whoever is behind it? For serious apps, I wouldnt let a third-party peek at anything I store, when and how. This is more like a toy.