I think the LC interview measures how determined your are. Are you willing to spend hours and hours to solve boring/meaningless coding exercises in order to pass the interview or not? Because even if you are smart and a good coder if you haven’t seen the problem before it is extremely unlikely to give optimal solution to 2 LC medium or 1 hard problem within 45 minutes. Your only option is to practice.

So if you willing to spend your free time mindlessly practicing, you will be a good ant at the company. Which is very desired since most of business programming is boring and repetitive and does not require creativity.

Also, validating the solution is simple. Does not need too much effort and creativity from the person conducting the interview.