My interest in WebVR is almost entirely for it's discovery and delivery advantages. Downloading, installing, configuring and running a native application certainly will always be the more reliable path to consistently high performance. If you want to sit down and devote some time and effort to playing "Elite Dangerous", native is clearly the way to go. But, for a quick demo or cat video snack experience, are you really going to install my app? I expect most people would greatly prefer the convenience and security of the browser sandbox for the small experiences.