Another disadvantage not mentioned in the post is that with coaster brakes the pedals can get trapped by the kickstand. I don't remember the details because this was a long time ago, but I accidentally found myself in a situation where I couldn't pedal forward because the kickstand was in the way, and couldn't pedal backward because the brakes engaged. I don't remember how I fixed it.

This is interesting, I recall having some of these as a kid.

I'd say the key drawback not mentioned is that, in many riding conditions (such as but not limited to riding when in close proximity to vehicles, riding in high wind, riding in proximity to severe drops or road discontinuities, riding with heavy loads, riding downhill with luggage encountering sharp bends, repositioning legs for a hard ascent, etc.) you cannot always freely alter your physical stance to apply additional pressure to the braking system (as it may upset other concerns) nor can you afford a short latency to reposition to your stronger leg before applying the brake (or a short burst of climbing on difficult terrain).

So while functional in most conditions, I'd say they are in fact objectively inferior in terms of latency and control and thus safety and utility in many realistic conditions.

What could be an improvement (and may have been made already) is a speed-gated clutch, that is to say, slow reverse is permissible but a burst above the gate speed enables braking. This could solve a minority of the issues in terms of control at the cost of complexity.

Damn well it was! I remember we used to play tag on bikes. But when we switched to hand brakes, it became impossible, as you need a free hand and speed control at the same time.

I have hydraulic disc brakes on my bike, and they are the greatest thing ever! Yeah, they require maintenance, but totally worth it.