Because you’re probably waiting with the crowd near where the smaller waves are breaking so you can catch those. Some people do just wait further out for the bi

Because you’re probably waiting with the crowd near where the smaller waves are breaking so you can catch those. Some people do just wait further out for the bigger waves, but they miss out on all the smaller waves breaking closer to the beach in the meantime. If you had more warning you could go out before anyone else sees the larger set coming in. Other people will usually see it in time to get there, but you’ll be first in line. That said, I don’t think it would be worth it. You usually don’t want to take the first wave in a big set anyways, because if you miss it then you can get stuck in the impact zone for the whole set.