About 5-6 years ago the gyms became much more honest in their instruction for new climbers, and will now actually say the quiet part out loud, which is that a backup knot is really there to 1. ensure that new climbers leave enough of a tail on the figure 8 and 2. are a way to prevent that probably extremely conservative tail from whacking you in the balls when you take a whipper.
sport gyms absolutely do not like people who insist on tying in with a bowline.