Cars can usually brake and turn harder than they can accelerate.
You also tend to spend more time on the straight after the corner, than in the corner itself
So you mostly optimise for corner exit speed, especially if the car has particularly slow acceleration and a long straight comes after the corner.
For F1 I was under the impression exit speed wasn’t as important as minimizing arc length of the turn.
They call that the geometric racing line and it might minimize the amount of time that it takes you to navigate one specific corner but if the corner is a hard braking zone followed by a long straight, your exit speed will likely be lower which will cost you time all the way to the next braking zone.
https://www.youtube.com/watch?v=uIbTPvHFf-w
https://driver61.com/uni/racing-line/