The main point is by removing the brew from the trub, you are less likely to stir it up when you rack to the bottling bucket.
And it frees up the big carboy for another batch.
I keg from the fermenting bucket after 2-3 weeks. All of my buckets have anti-trub fixtures on them.
Remember one unassailable statistic, as explained by the late, great George Carlin: "Just think of how stupid the average person is, and then realize half of them are even stupider!"
"I would like to die on Mars, just not on impact." Elon Musk