most people think of cards like originals, negatives, so better do not touch them directly
I also agree with that - which is precisely why it is not something I do very often. But sometimes if I am shooting a studio-type setup (not my usual work at all) it is handy to slip the card in to check on the proper monitor how the shoot looks. I know I could tether the camera for that, but that's even less my style.
I am not suggesting that you edit on the card. Actually we strongly recommend against that. What I am suggesting is that you just look at the thumbnails, select the images you want, and copy them. Don't tag, crop, rotate, apply IPTC or anything else on the images on the card. Do all of that after the copy finishes and only with the copies. Safer and faster on a local hard drive.
-Kirk