I want to move away from the "pack stiffeners" thing, but I wanted to point out that "soft pack" cigarettes are still sold to this day- with NO stiffeners used at all. The tight packaging (thin tin foil, wrapped in a thin paper package, wrapped in thin celophane) is all you need.
I like to think that these cards were just what they were advertised as:
Handsomely lithographed pictures in colors of famous professional baseball players in the major leagues, now in all 5c packages of SWEET CAPORAL, PIEDMONT, and SOVEREIGN Cigarettes....
Every baseball enthusiast in the United States should secure this superb series of pictures *pack stiffeners*

Start collecting today !!!!!

lol
Sincerely, Clayton