Ok, but some people have preferences like,

"I prefer to be in the back half of the first class cabin if it's a 757, but the front half if it's not, but never book the first or last row of first class (bulkhead) unless it's an A320-family (or another type that has a curtain between first and coach), and I prefer an aisle seat unless it's the last row of first class and the A/C has asymmetric seating in either first or coach (IYKYK), and I don't mind sitting in the back of the cabin if it's on the upper deck of an A380 or 747 (so please don't 'helpfully' move me to a row with a lower numerical value) but otherwise I don't want to sit in the back of the plane, and never book an exit row or the row ahead of an exit row, and only book the row behind an exit after confirming it has the normal amount of leg room and recline, and never book the first row of coach behind premium economy and preferably not the last row of premium economy unless the other rows only have middle seats; and I'm more willing to pay for first if it's a 757 and less willing if any other narrow-body, and don't book a first class seat if the flight is shorter than 1 hour and the premium is more than $25, and never book a middle seat in premium economy unless the only other available seats are in the last 5 rows of the plane."

It is obviously possible to encode that in a decision tree, but, for some of us, it's easier to just look at the seat map and pick what we want.