Yes, I assumed that the option existed, but I think you are going to see a lot of people who want their car to start charging right when they get home in case they plan to take the car out again that evening or even for emergency issues like what if a child gets sick in the night and the car hasn't started charging yet. Obviously won't be the case for everyone but I can see it being a reason to charge immediately.
Even if you plug it in right at 5pm, it doesn't actually start drawing electricity until later at night.
This feature it set just one time only, and works automatically forever afterwards. It's been common on most electric cars since 2013.