Clejuso #15 handcuffs. Why?

Sirs:
A friend from Germany gave me a pair of Clejuso #15 handcuffs. These are present day police equipment. They are about 1 1/2 inches thick and weigh about 48 ounces. 
Why would a cop in Germany choose these over the #9 Standard Clejuso handcuffs? I went to the Clejuso website and I don't think any of their handcuff cases are big enough.
Are these cuffs made primarily for collectors? So that one can say they have a pair of the heaviest swing-thru handcuffs made? Is it like the countries that issue bizarre stamps and coins so as to make money off of collectors? Am I missing something? 
The actual cuffs are enormous but the connecting links don't seem to be special, so I assume the weak point is that chain. So why make huge cuffs without a comparable chain?
 

Clejuso certainly has a thing for oversized cuffs! From the Model 13 to the Model 15, the cuffs so seem unnecessarily large in thickness. Then there is the Models 102 and 103 High Security cuffs that are also, very large. As far as being used for police work, i think these are meant more for use in transports. Where extra weight isnt an issue, as far as the officer having to carry them around with them. Shackle them at the facility, walk them to the transport vehicle and transport them to the court, doctor, hospital or wherever you need to take them. I have always scoffed at the Model 15, a bit. Its is just over sized for really no benefit. The pawl is massive and easy to access for shimming. The key hole is also pretty generous for allowing a pick or pick like device into it. The springs are really strong on the models 13 and 15, so that helps with slowly down someone picking the lock to open it. But, as you mentioned, the chain is a weak link on those models. Not sure why they didnt opt for something bigger? Even the Model 8 leg Irons ae quite chunky, by comparrisons to other leg irons, on the market currently.
-Rixchard Knip-

Thank you Richard. You have given me some ideas. I will run them past my friend in Germany and ask him for what he would use them for. When I got the 15s, I was speechless and it took me awhile to even come up with the questions I had in my original post.
Mike from Canada.

In the same year these huge cuffs came out, a  double handed, woven nylon corded tie came out. The plastic toggle of the cuff was about 1 inch long, making it about the smallest restraint and could be held in clenched fist.  Both ends of the scale in the same year, what were the people thinking?