I'm bet those high level BJJ guys are pretty familiar with the position and it's variations as a matter of course.
Back to the original post, yes, I think it's worth "developing". If you want to be a well rounded grappler, focusing narrowly on "high percentage" "techniques" is not in my opinion the way to train effecitively, especially for beginners/novices/. In fact, that is typically a beginners approach to learning martial arts...what works ALL the time, coach, I want to learn that!
Become a expert at Kesa Gatame and all it's variations and transitions to other positions and submissions, perhaps not, but it should be something everyone has some familiarity with. Especially escaping/reversing it.
In any case, I think that Kesa Gatame and it's variations deserves serious study by grapplers of of any ilk, particularly gi grappling, as that is what I'm obviously most familiar with. How far one takes that depends on training resources and purpose.
I use the kuzure version with side control and Kob pretty regularly.
So Hon Kesa Gatame ("hon" means "normal" or something similar for all you non-judoka out there) is easier to do at first (squeeze the head).
A note about Judo terminology...anything other than "Hon Kesa Gatame" that involves the "kesa" leg position and some sort of upper body control is considered "kuzure" (broken/modified" Kesa Gatame. This included things like Makura Kesa Gatame (Pillow), Ushiro/Ura Kesa Gatame), etc.
The version of Kuzure Kesa Gatame that PSB is speaking is the version of Kuzure Kesa Gatame illustrated in the Katame No Kata of Judo, the katame waza (choke/pin/armbar plus one lower body submission) kata of Judo.
Kuzure as defined (katame no kata version) IS a versatile hold for sure. I prefer it to the Hon variation as well, although I won't pass up Hon Kesa if offered. I know of (but cannot necessarily do anymore) 6 or 7 submissions from the Hon position, depending on how uke tries to escape. I am sure there are more.
I've rolled with good BJJ guys, and it's the truth that holding them in Kesa Gatame is very difficult if not impossible to do for very long. The same goes for judoka who are good on the ground. That includes one black belt (BJJ)...but I was able to transition and maintain control for a while at least. And that's the nature of the "game", be it Judo or BJJ.
So I say to the OP, try and see that is the only way to find out. You will learn something useful, even if you can't pin Roger Gracie with it...