Back when I was working for smp we used to see hundreds of those round protectors on the big tann RDV’s used by one of the big supermarket chains.
Personally i really liked them as they were nice to work on and it was the same old problems that used to arise so were pretty predictable.
But, it was just as well the majority of problems were easy solved as the locks were held together with hardened shear screws and from memory zero parts including blanks were available. This was through the 1990s to 2000s and iirc kromer were still around back then but weren’t supplying the essential spares that were desperately needed.(just like fichet bauche). As a result, most, if not all the protectors got converted over to the 520 locks.