My limited experience of it tells me it doesn’t work against someone who knows how to fight.
I’ve been doing Muay Thai for about 18months now, and a friend of mine has been doing wing chun for about two years. We sparred a bunch frequently, and although the wing chun stuff worked initially, it was pretty easy to figure out how to get around it with feints and fakes. I’m talking, like, after only a couple of exchanges. If your opponent knows how to keep their distance, wing chun isn’t very effective.
I get that neither me nor my friend are particularly highly experienced, but that’s how it went.