I have never been able to truly grok (I hate using that word now, but it fits) what this could even be like. Though I imagine it's like explaining sight to someone who was born blind.

It doesn't, though, not usually.

If it does to you you're even more of an outlier because that's (weirdly enough) the one place where most of us can see inner pictures.

I can't see anything while awake but I dream just fine, and statistically speaking that's more common according to the miniscule amount of research that exists.

I wouldn't say "obviously". I don't know how different from normal people's dreams mine are but I can't visualize stuff but still have pretty visual dreams usually. Not always, but I assume it fluctuates for everyone.