TL:DR - There is some value for kicks above the belt in self defense, but they are not for the beginner or intermediate martial artist.

My thoughts:

As you learn to kick higher, you learn how to apply power throughout the kicking range - if you can kick with power at head level, you can kick with power at any level below that as well, so if there IS a moment when a higher kick is the correct response to a SD situation, you will be ready to apply it... the opposite is not true. If you only practice leg kicks, you will be ill-prepared to deliver a powerful kick anywhere in your range.

A well place groin/hip level, or solar plexus, liver, neck or even head level kick can be devastating, and fast enough to prevent take down, especially if the opponent is already off balance from a hand strike.

A full speed kick should never be caught without doing severe damage to the person attempting the catch.. bjj or not. Otherwise, catching kicks would be a #1 move in MMA... which it is not. Even in the octagon, head level kicks are used to great effect, and those are top level fighters with serious ground game.

The reason that you see this being repeated SO MUCH in the RBSD world is the "R" part of it... the RBSD guys are teaching and training in systems that will work by removing things that will prevent an effective self defense for the vast majority of people learning.

They are designing a SD system that will protect the seasoned hard-training martial artist as well as the weekend warrior who trains 4 days per MONTH... and the soccer mom that goes to a weekend seminar will even have a shot at getting through it without too serious injury. The idea is to stick to the things that are going to work regardless of fitness level, regardless of abilities of the attacker as well as the defender. Break it down to the basics.

Knee and groin strikes are easy to perform regardless of fitness level, hard to stop, and reduce the chance of getting taken down when you are on one leg (vs higher kicks).... So SURE - makes sense!

Unknowns that all RBSD systems have to deal with:
Opponent skills
Your skills
Multiple attackers
Prevent going to the ground

If I am teaching SD for a seminar... or if I'm teaching it to most students... kicks stay below the belt AT ALL TIMES - to reduce the chances of takedowns... but serious MA that would rip your arms out of their sockets if you managed to catch a kick? They should not be so limited.

If you train for kicks in self defense, full speed, full power, you should not limit yourself to ONLY low level kicks once you have developed sufficient speed and power, as you are limiting your tool set, which is never a good idea.

I'm probably not really saying anything new here, but articles on self-defence are written for people who don't have access to face-to-face training from amazing martial artists on a weekly basis, right?

If as a group-- not singling anyone out here!-- we cast our minds back to before we ever did martial arts, what did we picture when we imagined being kickass as self-defence?

Come now. Be honest. Who else assumed the coolest looking techniques, the ones that were used in those carefully choreographed fight scenes on TV, were automatically the most effective techniques? Who else thought that if a basic knee strike to the groin could be effective, then anything that took more training to master, e.g. a flying side-kick to the head, must be automatically better in any given situation? Otherwise, what would be the point of it?!

Er, look, I utterly refuse to believe it was just me.

So. Given the target audience, it must surely be essential to address Hollywood Self-Defence Myths first off, to dissuade readers from trying to kick above the waist as a first resort.

As someone who goes to martial arts classes, I have been advised that in a real-life situation, low is generally better. I think all beginners need to be told this, but the interesting thing is, even if you're not told that, you'll work it out once you get to practising martial arts at an intermediate level. You are going to notice in sparring that you lose speed above yay-high, and your partner sees your foot coming. (Then you'll try to fix it so you can be like that guy/gal in the club who kicks at lightning speed at any height.)

These self-defence articles and quick self-defence courses are aiming to save their audience members from only discovering at the worst possible moment that they can't pull off a Hollywood-style kick to the solar plexus, and finding out exactly how slowly their untrained foot moves while trying to survive a violent attack. A good, noble aim, imo.