I was including wireless local cameras in that, admittedly loose, 'cloud' definition due to the instability wifi introduces.
A long as that cloud is your own: ie another site you own, or a VPS; mirroring the local storage the cameras are wired to, alright. But not as the primary and only destination.
There's been plenty of examples of cloud based systems you subscribe to (ie corporate online storage only), cutting off user access, shutting down, having their own network/systems issues, providing data to third parties including authorities without warrants, etc...