The cellulose acetate they both use are likely slightly different. I have to assume the material Kem has chosen leads to more to bowing. That said, Kems stock probably remains unchanged for other properties it possesses. I have to imagine casinos feel it’s extremely durable and doesn’t crease or mark as it’s the card of choice in every major casino in AC and Vegas…and many other places. I would guess they have 90+ percent of the market for casinos. I play mostly in Atlantic City, have played in Vegas at several casinos over the years, I play in Boston at the Encore when I travel there, and a few other casinos in PA other places. The only time I ever saw Kem‘s NOT being used was at a small tournament at Harrahs in AC around 2016. And that was only once. They were using Gemaco Superflex, but it was only for the tournament tables. All the cash tables had Kem cards.
I once asked a dealer at the Borgata how often they throw away a set up of cards as there are notes on their boxes. He said about once every week or so…..but they are being used and shuffled 24 hours a day 7 days a week. That’s likely several years for of use for most people.
Also, I have a setup of a Kems from 2003 that were used once a week for about 4 years. They are completely flat and stayed that way before I found out how to best store them. I hypothesized that the constant play and the oils from peoples hands kept the humidity out of the decks. There are a bit faded, but anre absolutely still playable. I retired them for sentimental reasons as they were my deck from the poker boom era. I also have 30+ set ups now! The deck I’m playing with now bowed and is from the year before the poker boom. I didn’t play with them as much as they were poker sized and I also took them down to a beach house a few times