What I don't understand is why these medals do not show up in Numista.
Numista isn't a complete collection. I have many commemorative medals of WWI from multiple belligerents that are not in Numista.
Numista is a user-supported numismatic database. Its listings are there because one or more collectors created/contributed to the listing. If no member collector creates an entry, it won't appear in the database. If you have pieces not in the database, you could benefit the numismatic community by joining Numista and adding to the database!
Collecting history one coin or medal at a time! (c) commems. All rights reserved.