It is my understanding that you roll in what you need to "flatten" and "reduce" the sail for the conditions. I think the comparison to slab reef points doesn't really work as this system is variable - set what you need.
I suspect that these systems are not targeted at the "purist" sailor which equates to a tiny minority of the sailing population. Some of these roller furler mains are getting some really good reviews on their upwind and overall performance and speeds that work for me. Couple that with ease of use and it's pretty attractive for most sailors.
Catalina 36 MKII