It's double vision, each eye still sends its own signal back to the brain. But I usually just try to focus on one eye's image so I don't get sick haha. I am able to read if I focus one eye, I'd say when I do focus on one, the other eye will still notice movement and color

It's kind of an overwhelming sensory experience, possibly because I don't do this very often

If your brain had always used two independent eyes, you'd have a Brian that uses them just fine.

Anyway, not the parent commenter, but I do lazily let my eyes separate on my phone in bed when it's close. My understanding is my experience matches those with lazy eyes. You end up picking a dominant view and the other kinda fades away.