Just to be clear the paper is drawing fixed icons, so there's no real FOV. (The contact follows your eye). You could probably make a 7-segment display and such with this, but it's not pixels. There are batteries that can fit into contact lenses already like with Mojo's setup. That one has a monochromatic MicroLED display which is quite a bit more advanced with eye tracking and does what you're thinking.

Since electrochromic uses so little power it can probably run for a while on a small battery though displaying directional symbols, time, or simple icons to the user. The supplemental videos at the bottom shows how fast it can switch and shows various patterns they printing turning on and off.

I quite like how transparent it is when in the off state. There is a optical device for AR displays called an opacity filter that hasn't been invented. If they can get an electrochromic solution to go from transparent to opaque black with a lot of levels and make the resolution high enough they could have a really nice product. (If it switches at 240Hz+ though. That's probably the deal breaker as this switches very slowly).