They are Super-Index (which are great IMO). My favorite KEM decks are "Monaco" & "Kent" Super Index.
Unless they are a super rare deck, cards are meant to be played with.
It's funny you say that. In the past month or so, I've been "gathering" sets, to find "my" grail. Man, it's been a journey. I had COPAG, poker for years. Wanted something different.
Moved to bridge and wanted to continue with jumbo.
I've gathered: Modiano, Guild, Fournier Congress, Fournier FDL, GEMACO Superflex, Grand Victoria (GEMACO Superflex), Davinci, Bicycle Prestige, Piatniks. All have their pros and cons. The cons are typically a tad too slippery - not sure which, if any brands, will break-in, in that regard.
One thing I noticed, nearly all of the sets have shaded centers. These KEMs do NOT and I like that. Man, they feel a tad thin though, like they'd bend, but I might have to give them a whirl on the table