Since the Sans Souci 12 1/2 cent chips say "card room", I don't think it was used as a "mini-snapper" to pay off 25c low-limit blackjacks.
I think it was used in PAN games, which would have been dealt in the Card Room. Fuller's Index shows that Pan was an approved game there.

On the other hand, the downtown LV Club Bingo 12 1/2 cent chip was a mini-snapper, used on their (single?) 25c limit BJ table. TCR shows that 100 chips (1 box) were made, which would be consistent with a mini-snapper order.

FYI, according to TCR, there's one more 12 1/2 cent Nevada chip out there, but I can't recall where from right now.