Are you suggesting a zero-zero approach?
Are you asking about a zero-zero approach, or an approach to published minimums? These are two very different things. The former I would only do if I had fumes in the tank and no other out. That would be the result of many failures along the way, poor planning being one of them. The latter is no different than an approach to minimums with steam gauges.
I think you're asking if the syn-vis picture is accurate enough to land in zero-zero conditions. The published accuracy of WAAS is typically on the order of 1.5 meters horizontal and 2+ meters vertically. Assuming you have the field altimeter setting in then you'd be accurate to that, which is only required to be +/-50 IIRC. Are you landing on a narrow runway, and 1.5 meters to the side means a tire off the edge of the pavement? Are you landing on a runway so wide you could probably put it down perpendicular to the runway?
I guess I would take a look at the numerous syn-vis videos available on YouTube and see if you think the sight picture presented on the screen is close enough to the sight picture out the window. In nearly every one I have seen I can discern offsets laterally that would be alarming to me if I was trying to put the plane down without looking...