I'm guessing its for when you snap a half shaft or something along those lines where you can't drive it up and need to push. Been there done that It took several of us to push my car up onto the trailer. Would have been real nice if there was a winch.
That is what I thought.
The OP mentioned he was on a budget.
Buy a "Come-a-long" for $50 just in case he ever has to winch the car up.
There are always people at the track willing to help push the car on the trailer.