I don't doubt it's an infomercial for the reasons mentioned, but being an infomercial doesn't necessarily mean it didn't have more than just the one episode.
For one thing, the circulating episode has a contestant plug, with the announcer clarifying that it's also if viewers want to be an audience member or at-home player. I doubt they'd include any of that unless they planned on following through.
Secondly, the lifespan - Newspapers.com's archives have TV listings for the show between September 4 and October 1. While it's pretty slipshod from station to station, the airings are frequent enough that I think viewers would've caught on if it was just the one episode being shown repeatedly (though that could explain why the show was seemingly here and gone within a month without fanfare either way).
Thirdly (and this may not amount to much but hey), the May 2, 1989
Weekly World News (of all things) had
a blurb on Cynthia Brooks (the show's prize model) that mentions "the TV game show
Shopper's Casino" (along with "the recent flick
She's Having a Baby" and "the series
Rocky Road"; IMDB lists her for the former, but I've found no indication she was on the latter). Yes,
Weekly World News is a satirical tabloid-type rag, but it's still an obscure grab even at the time given
Casino's brevity.