I am of course assuming you have mirrors on your car and have just chosen to not use them.
There are instances when one can reverse a car without the necessity to use the rear view or side mirrors (like being in the middle of an empty football field or being the last person alive on earth), but none of them are relevant to this question.
You can see where I’m going with this…
The reason for the mirrors (surprise, surprise) is so that you can see where you are going when you are going in the opposite direction to that which you are facing (ie reversing). Obvious answer here is, ‘just turn around… and you’ll be going in the direction you’re facing so no need for the mirrors‘…
Perhaps EXCEPT for one minor difference, the steering wheels are no longer in front of you but are now BEHIND you.
Let me give you an example.
Take a classic supermarket trolley and you’re happy to push it around. Now switch ends and push it the other way, from the front… not so easy huh? Bit difficult steering it now, isn’t it? Why, because the steering wheels are at the back – exactly what happens when you reverse your car.
Suddenly you need to be looking in two places at once, the direction you’re going in AND what the steering wheels are doing. Easy enough when they’re both in front of you but near impossible when they’re in opposite directions.
…and that’s why they invented mirrors for cars!
Now you can look where you’re going AND still look at what the steering wheels are doing IRRESPECTIVE as to whether you’re going forwards or reversing (with mirrors).