Shooting from the hip here (a bit of an unsophisticated answer), but yes there must be. Unless your campaign is so loosely targeted that it will hit the nail on the head first try (a campaign whose objective is to just get brand exposure to a large, general audience, I’m sure it can do that right out of the box) – but if your objective is anything more meaningful, like link clicks or conversions – yeah it’s going to have some time to settle in. I’m assuming it learns over time from different indicators to determine who is more likely to click (or convert, follow, etc.) based on a variety of factors, and it takes time for the algorithm to test and see what the real indicators of interest are. It would be very … odd & specific situations where no learning period (testing by the algorithm) was needed for optimal performance