Do what works for you. But I drop at least a dozen trees every year, and can only think of 2 times in the last 20 years I ever needed to actually winch a tree over. I'm not opposed to stringing up a safety line, in cases where you want to be really sure it can't fall over backwards, but there's a big difference between a static safety line and actively winching a tree over while you make the back cut.
I don't encounter many trees so badly back-leaning, that they can't be easily pushed over with wedges in the back cut, with better safety and speed than rigging up a winch.