The writers and producers wanted to show that Buffy’s attention to training sets her above Faith. The amount of time Willow gives Buffy to not stake Vampire Willow is pretty much the same amount of time that Buffy gave Faith to not stake Allan Finch.
(Excludes most of the package films. Some films, eg The Lion King, are impossible to pin down exactly and some, like Aladdin and Treasure Planet, are anachronistic, so these are estimations. A few have been split into 2 if there is more than one time period in the movie, and sequels have been put together.)