I have used picture framing "matte" board for fin material for beginner-make-n-take rockets. For that specific use, I like it better than balsa because the kids can turn it around and use any edge (except the short one!!!) without worrying about grain direction. This adds to the design flexibility and gives them a few more style options.
However-
After these cardboard-type materials are glued in place, if a fin gets bent the cardboard material "splits" and weakens. This can be fixed on launch day with a few drops of cheapo superglue, but it leaves an ugly blivet on the fin. I would say that cardboard/fiberboard fin materials are good for one-flight-wonders, but you are pushing your luck after that. They often don't look so pretty after a while, and I don't want them on rockets that I plan to keep for a while.
You could improve things a bit by soaking the edges of the fin with superglue and trying to get the CA to soak/wick deeply into the fin material, but you need to do this AFTER the fin is completely attached to the rocket. (The superglue leaves a "plasticy" finish that does not let white or yellow glues soak in, so you must complete the fin root structural joint first before trying to soak the rest of the fin with CA.)
Even though it "can" be done (using cardboard and fiberboard for fins), I still prefer balsa and basswood and ply.