Your crawl space rests under your home, typically in the dark and underneath the surface of the ground. That means it’s often very nice and cool in the crawl space.
This isn’t inherently a bad thing. In fact, it can be a very good thing. It only becomes a bad thing when you introduce warmer air through a crawl space vent.
Because of how relative humidity works with cool air, you’re always going to have the problem of condensation when you have crawl space vents. A crawl space vent well is only going to keep out already-condensed moisture. It’s not going to do anything about the new moisture this process is constantly creating.