5c Adolphe Postal Card with Illustrated Advertising

Unsure what it is or what it does!

Luxembourg-Gare
7 Nov 1902
to
Berlin, Germany
9 Nov 1902 

Printed backs with illustrations on government-issued postal cards are uncommon. This illustration is especially well executed, although the machine's use remains for a reader to explain!

MARIE ADÉLAÏDE - Die Proof on Glazed Card by Schirnböck

Die Proof on Glazed Card

Reverse inscribed in manuscript: 

Luxemburg 1914 Großherzogin

with Red Handstamp:  

Nachlaß 

Ferdinand Schirnböck

Believed to be unique.

Unusual Rates: Registered Printed Matter

29c Rate

Registered Printed Matter!

Wasserbillig

20 Nov 1916,

Trier Censor,

 to Eisenach, Germany

22 Nov 1916

Handstamp:

Drucksachen

Einscriben

4c Printed Matter Rate to Germany

(but Basien-Hoffkamp shows the 4c rate

increasing to 5c on 1 Aug 1916)

25c Registry Fee

What purposes were served by registering printed matter?  One can only speculate.  Perhaps to be sure the recipient (here a seller of construction materials [Baumaterialien]) received the information, and certainly a registered letter would not go unnoticed in the incoming mail.