That would assume that a majority want it on by default. I almost never use it, myself. It's slow and doesn't work when you're in other intelligent flight modes.
I do use other slower/safer modes, such as tripod and cinematic modes, but they too are slow. Sometimes you want to get to a location faster, then turn on a slower mode for smoother video. You don't need the extra safety when you're flying clear, well away from obstacles.
Also, if you're are shooting a wide landscape from a high altitude, those modes are TOO slow. A normal speed looks better on video and is plenty smooth for straight flying. Though for this, you want to tweak your EXP / sensitivity / yaw / gimbal settings to be smoother motion from default (there are other threads for that topic).
Chris