The elbow in Wing Chun, as Sifu Lam demonstrates, is used in specific situations (to break a hold) and not (as in Muay Thai) a general weapon. This is the Biu Gee (third form) elbow, so think of it as an emergency technique, not something you do on purpose as part of your strategy. It is an escape.
Muay Thai uses range differently than Wing Chun.
They attack from a long distance (kicking) and they attack from the elbow range (clinch, bloody elbow).
Wing Chun’s specialty is the Tan Distance or bent elbow range. The whole system is designed to develop your capabilities at that distance and to get you in and out of that range as necessary.
We must always get back to our preferred distance, like the alligator, which pulls its victims to the bottom of the river, where it has the advantage.