“There’s one quantum extremal surface that gives you the wrong answer — the Hawking answer. To correctly calculate the entropy, you have to pick the right one, and the right one is always the one with the smallest quantum-corrected area.”
I wish they explained why that’s the criterion for the right one.
Occam’s razor............................
Because they say so. There is physics which deals with the real observable universe. Then there’s the mathematical physics which is sometimes applicable and useful and sometimes just pointless rabbit-hole exercises.