5 J seats available LAX-ATL, only 4 showing open
 

So... should I pay the $700 upgrade and assume I'll sit next to someone famous? 😂

https://cimg2.ibsrv.net/gimg/www.fly...b68d13d6ac.png

As famous as Federal Air Marshal =)

Not sure what the question is. Are you assuming 1st has mostly famous people?
Or are you asking about why it shows 5 tickets available, but only 4 seats showing open? (that could be because of a blocked seat, or DL getting very aggressive with overselling)

While I realize the famous person part of the post is tounge-in-cheek, chances are what is happening here is what I've heard from the agents before as a "hung" seat. Meaning, somewhere along the way someone had purchased, been upgraded, seat-change, etc and the computer still sees it as being occupied even though it isn't. So it got "hung" up on the seat map side, but not the reservation side. Happens quite frequently in just my personal experience.

That being said, is around 3 hours and 50 minutes roughly of travel worth $1700 to find that famous person?

Apparently there are a fair number of folks that will pay it, with or without the chance of meeting somebody that is "famous". LOL!

Since it's refundable, I would book it and demand my money back if I don't sit next to someone famous. Well, maybe on a sliding scale:

I want half back if it's not even a B-lister, and three quarters if they are famous only in their field, like the glue king of Sacramento or a starting athlete in a sport I don't follow, like badminton. Hmm, and if they were nominated without winning a Golden Globe last week, I want 25% back.

Agreed, for example I recently had a J return ticket MEL-ATL-MEL, DL flight was a VA codeshare. I changed my return date on my VA issued ticket. My DL reservation then showed my new return and my old return. My new return was earlier, but even after I got home, I was ghosting on that second ATL-LAX flight right up until check-in. I could still change my seat, etc. Just for fun I tried to check-in (because the app prompted me to), but it said my reservation had no e-ticket associated with it.

So sometimes reservations and seat assignments are in the system but not valid.

At those busy airports, you should probably figure 4.5-5 hours total time on the airplane.