But the cloud IS someone else's computer. I don't own it. So if I put my data in the public cloud then by definition it is on someone else's computer. You can

But the cloud IS someone else's computer. I don't own it. So if I put my data in the public cloud then by definition it is on someone else's computer. You can extol and iterate the virtues as much as you want. You can provide guarantees and demonstrate all sorts of benefits. In the end, the general cloud computing environment is still not yours: it is someone else's computer. Even if you are renting it. Which is fine. Sometimes that is good. Sometimes not so good. Sometimes you want the flexibility of spinning up a few hundred or thousand hours of server time on machines you don't have to own. Other times you want a private cloud. I've worked several projects where a private on-site cloud was significantly cheaper to operate than a public cloud. The in/out costs smashed the cloud savings. Flip side, a project needed to be able to rapidly spin up machines as needed from a template, public cloud was the only way.