I don't see very many of these and I am curious as to the criteria for the use of the wax seal. I have handled many thousands of waybills over the years but I have only run across about a dozen with seals.
What does the seal say? Was it even applied at a station or was it applied by the sender. Since the document refers to a declared value, this was insured. The wax seal may have been a security measure to see if the item has been tampered with.
This first one was a package worth 1,000 Francs sent from an agency of the Bank of Brussels (since 1975 Bank Brussel Lambert) in Gembloers (Namur province) to the branch office in Namur itself.
The second was sent from the Hasselt branch office to the Eisden office and insured for 1,000 Francs by Europese Maatschappij insurance. This will have been the Belgian company. In 1907, Max Engels founded the Europäische Güter und Reisegepäckversicherungs-AG that insured goods and luggage. There were another 22 of these related insurers across Europe. They cooperated with railway companies.
The weights suggests these were not banknotes. Maybe checks.
The top one is the agency in Gembloers of Bank van Brussel (Banque de Bruxelles SOC.AL.). I cannot read the final word on the rim. It looks like "SOCIALE." The lower one is from the Ciney agency of the Generale Bank van België (Banque de la Société Generale de Belgique).