Like all moves, nothing is 100% we need Miguera to put you in kesa and have you try and escape and we can see who's more accurate. I personally love using kesa to transition to knee-on-belly when the person tries to come up and take the back. Or I transition to NS. But I also recognize getting your back taken is a risk.Seems to get years and years to master it. The only 2 guys that I'm not able to take the back when they try it is a guy who has been doing this move for 13 years and the other is a judo coral belt and BJJ purple belt.
All the other guys even judo black belt and brown belts (but BJJ newbies) I can take the back or reverse them when they try it.
The way I play my RDLR and half guard, I pretty much provoke the kesa gatame, I give the knee slide but not the underhook. So it's kesa gatame or back step for them and I'm ready for both. Sure if I let them settle with a good grip on my sleeve I'm done but there's holes in the transition for me to attack.
We have some kids in the kids class who do BJJ and Judo and every time they try a scarfhold they get reversed or back taken.
I only really do it when it "feels" right and I can tell I can smush my opponent. Not really a go-to move, but it's certainly effective. Miguera might be really good at it, his username is Japanese.