Well, you could place a bug between the VNC and the VPS parts. Or your government might force you to do it. How can you reassure me that isn't the case?
We are still in a limited pilot program, but one of primary things we are testing is how to ensure that your computer is not compromised in any way.
We think that if we can achieve the technical goals then arguably, having a remote machine is more secure than one that someone can take from your house/car/etc.
That said, it is a really hard technical problem to manage a computer for someone without having any access to it and that is something we are designing out now.
Furthermore I'd argue that if someone steals your machine from your house/car/etc, getting the keys to any remote machine should be trivial just by looking at the stored passwords and configuration.
But maybe I misunderstood what you were saying, sorry if that's the case.
Abdicating responsibility for personal security to ANY 3rd party makes one less secure, period.
Now, when the government comes knocking, instead of handing over some files or access records, you'll be able turn over the user entire computer. That's the exact opposite of security to me.