When talking about VR Images resolution really matters. While a user in VR is only looking at a small portion of the overall image at any one time the image must carry all the visual data.
So lets look at how this works. The chart below illustrates the relative size comparison from Standard TV, through the variants of HD and into Ultra 8K resolutions. As you can see the amount of visual data in standard or broadcast TV is only 640 pixels across the horizontal axis, while 8k carries 12 times that amount with 7680 pixels.
As I write this, the standard today for VR display goggles is 640×800 for each eye for a 2D image the amount presented to the viewer would be this.
And if we split that in half for 3D images it looks like this.
2D images must be over HD for there to be enough pixels to even fill the screen
and if we go to 3D 360 we are up to 4K and still to not have full vertical dimensions of 800
Which is why most people stick with left-right 180 for 3D
Keep in mind display equipment keeps advancing. Working with a standard, which is standard today, will leave your hard work looking very rough when then next generations of display technology hits the market.