Since most of my time at airports are spent through work, I long since learned that fast track + getting access to the lounges makes a world of difference.

Free food, drinks, booze, superior in every way. If I know I have access, I’m not too bothered with spending extra time, or minimizing my airport time. The absolute minimum should be fast track tho.

Edit: Also, the real benefit of upgraded class when boarding is guaranteed overhead luggage space, if you only have carry-on luggage.