Does elite status offer you anything special if you are already in paid First or Business Class (best available cabin)? The only thing I can think of is bonus mileage, and one can decide for themselves if that is worth it. There is no need for an upgrade, and you already get priority boarding, check-in, and in some cases, priority baggage. If your airline offers lounge access for free to elites, they probably do as well to First or Biz (that's most non-US airlines, exception Delta).

The root of this question is if you are loyal to and have status with a certain airline, is it better connect on them vs flying nonstop or making an easier connection on an airline without status, assuming you are in paid best-available cabin.

BizJet

United gives on-board entree choice priority by status in domestic First and Business class cabins most of the time. That's really all I can think of.

I fly nonstop on any airline that offers it, if my time is very valuable at the moment. Over the past few months I flew direct to CVG on DL because it was direct, I flew TWA to STL because it was direct, etc. If I have the time I will probably stick with US or UA and connect, but when time is precious why jeopardize things with a missed connection, the extra hassle and wear and tear?

In SFO on an F transcon ticket I learned about the secret lounge they have for VIPs and for full F people and that was nice, you can't get that on an upgrade. I have since learned they have these at LAX and other airports although at IAD nobody's ever admitted to it or offered when I asked (and was flying on a paid F ticket)

After posting it, I realized that what PremEx mentioned is the only thing I could think of. And that's only on United, no other airlines in my experience.

In regards to that United program, who gets the meal choice first: 1Ks on upgrade or non-status revenue pax?

Richard makes a good point too: More often than not, paid FC, status or not, gets you more than a status upgrade. This is only true on "premium" flights I think.

If your flight is cancelled or delayed and you need a reroute, will your experience be better as a coach/upgraded elite or non-elite First pax?

On United, it's status regardless of fare paid. The on-board manifest only shows status and does not indicate what fare was paid or if the pax has been upgraded.

DL doesn't denote upgrades on the manifest either. If you are high elite, they will sometimes ask your meal preference first, this perk is hit and miss. Besides the fact that the flight leader will often greet you specially and make small talk (sometimes embarrassing) there isn't much else when flying in front. On the otherhand, if you're already flying upfront, no airline gives you much extra for status.

In reality, there is not much they can do

In my experience with Delta with all four levels of status (Platinum, Gold, Silver and none), there is absolutly no difference in how I'm treated on board in any class.

The benefits are pre and post flight (upgrades, bonus miles, etc.)