Just What Would You Call These?

This example happens to be from Argentina but I know lots of countries have something similar. Sometimes they are issued in conjunction with a Philatelic Exhibition and can happily be included with ephemera and memorabilia associated with them, but more often they seem to be issued alone.

I most cases they are a printed card, sometimes like this one, folded, sometimes flat and with a stamp or stamp set cancelled with some sort of commemorative postmark. This one is numbered on the back but that is not all that common.

The cancellation seems to be a First Day of Issue but it is not an FDC. It is not a Maximum Card, with or without a First Day Cancel.
It is not related to an event, as a fair or Trade Show, and other than the reason for the stamp issue itself it is not connected to an anniversary of some sort.

Just where in the galaxy of stamp collecting would you fit items like this?

For me is a First Day of Issue presentation Folder. Although there seems to be a discordance between the postmark date and the one stated on the card, it is very likely that the scheduled issuing date was October 9th, 1949 and then, for whatever reason, it was delayed ten days. If the cards were already printed, what was wrong on using them?
I know that for anglosaxon minds it sounds illogical, but not there...