See the "it's not technically impossible" part of the comment, which was meant to preempt (unsuccessfully, it seems) such replies.

Yes, but I assumed that meant without a lot of work or obscure settings and stuff. This is a headline promoted feature of the phone and its software.

No, I more meant that it's a huge hassle. For example, with the phone you can't compose very well because you have to wait for each frame to expose before you can make a correction. With the SLR viewfinder, you can just look and see what's going on. Then you have the issue of not being able to capture a specific area using a narrower lens (if your subject requires it), and just the experience is going to not be great.

I think with a phone in a tripod you can use an app like google sky to get it pointed at exactly what you want, and even use search functions and stuff.

There are narrow lenses for phones as well.