[LoSboccacc]

most obvious reason: gusts. wind is rarely stable in intensity and direction.

a secondary point: checkout any landing strip https://i.imgur.com/n99YiM5.png

a plane can't pinpoint the landing to absolute precision, even on autopilot. the dark patch should give you an idea on how much ahead/behind a large plane may land under real world condition - all the test they give in the papers are using small planes or even fighters, those can manage precise landing, a 737 not so much

the plane will have to follow the turn until it touches down, and as it follows the turn it'll change it's direction relative to crosswind, with all the implication it entails. few degrees on landing are already enough to need a significant correction.