Yep that is the safest option when you don't have a recovery point.
However hitch receivers are better because the strap is able to slide on the shackle to the correct angle if the snatch isn't a perfectly straight pull. It also reduces the likelihood of damage to the end of the strap, as pulling it against the square reciever can fray the side of it.
But as I said, infinitely better than a towball.
Cheers