Judo chokes and strangulations are effective offensive combat techniques of inducing brain damage (reversible, irreversible, or lethal) through creation of oxygen deficit in the brain by restricting airflow (‘choke’; ‘air suffocation’) or blood flow (‘strangulation’; ‘blood suffocation’), that burred in a lot of misconception.
First and most important – chokes and strangulations are not self-defense techniques.
Second – chokes and strangulations are lethal techniques. Their lethality depends on the duration of the application.
It’s really surprising like, even otherwise reliable, sources defining Judo chokes as means of “subdue violent opponents with temporary unconsciousness”. Let’s be clear – it can be temporarily in one of the only two cases: you’re not completing the application of the technique or/and you're applying a recovery technique. In the real combat both aren’t an option.
In case of self-defense you don’t have the luxury to carefully calibrate power and duration of your application or to apply recuperation on your victim (if you do, it is not self-defense).
In offensive (military) combat you have other, more simple and secure, ways to induce unconsciousness when taking live prisoner without risk of killing him (for a recon team snatching an enemy soldier for interrogation just to find him dead before he’s able even to say his own name, is a devastating blow). In quiet taking out of enemy sentries, garrote is preferred use instead of bare-hand Judo-style chokes.
Those two reasons enough to leave this subject alone as we talking about Judo for self-defense. However, chokes seen are as an integral part of Judo technical arsenal and this I would like to address.
Chokes are legal sport techniques of all Judo styles except for traditional SAMBO (American SAMBO Federation’s Freestyle SAMBO permits chokes). This fact contribute to the confusion about it applicability in self-defense as in a popular view the danger/lethality of a technique based on the group, it belongs to, and progressing from sport techniques to self-defense techniques to military combat techniques. This popular view place chokes and strangulations into the “innocent” sport category. However the applicability of an individual technique in self-defense is based not on its classification group, but on the set of entirely different factors.
The other question is why chokes aren’t permitted in traditional SAMBO and if it makes this style less effective.
I don’t know what exact considerations Vasili Oschepkov had when he restricted chokes in his Judo style, but I think it was the same as behind common long term Judo practice to include choke study only into training of senior level adult students. In his tragically short life Oschepkov just had not enough students on this senior level to start introducing chokes.
Is absence of chokes in traditional SAMBO makes it less effective? I don’t think so as chokes are the narrow niche technical elements with limited applicability.
Should Judo chokes be studied and used? Absolutely yes, as long as we understand their limitations, risks, and applicability in sport Judo styles.
Should Judo chokes be studied in self-defense classes? Yes, as we need to study defense against them and it can’t be done without studying the proper and the most common (two different things!) choke attacks first.