I don't consider falling from a non-moving bike a "horror" story, more like an embarrassing one. And I don't think you'll find many arguing that clipless pedals aren't worth the effort.

Not remembering to clip out is merely one of the many ways you could fall due to clipless pedals. I've never forgotten to unclip, actually. Most people don't fall on their first ride with clipless pedals, but a few rides later, once they have gotten a bit complacent and are no longer as attentive. For my first fall, I had completely stopped and put down my right leg, while leaving my left clipped in. Buddy of mine rode up on my right and I instinctively moved over a bit to make room for her. That that caused me to lean too much to my left, overbalance and fall onto the left side, due to not being able to clip out my left leg fast enough.

It takes a while for your non-dominant foot (the foot you leave clipped in) to have enough muscle memory to do an emergency clip out when that happens. Now that the muscle memory is there I don't fall on my left side anymore, though from time to time I've had to do an emergency clip out to save myself from falling. Maybe you'll end up being one of the lucky ones and not fall. Maybe not. Who knows. Not a big deal usually.