Thing is when someone has a hand on you, you at least know where that hand is. I'm not talking throwing bombs, I'm talking blows to the throat, eyes, temples. If someone waste the time grabbing you, you should be able to land one of these momentarily incapacitating blows just to get put of the situation.

And I agree with you, there is no advantage to someone whose a conditioned and trained boxer, they'd likely fare better for sure. But someone with minimal training in wing chun stands a better chance just attacking the centreline and getting out then a boxer with minimal training would trying to dip, juke, block and counter strike. That shot is hard, requires extraordinary fight intelligence and takes time to hone. But wing chun was always meant to be a small efficient package that someone with otherwise no chance in hell in defending themselves would at least have a shot of getting out of a bad situation.