use USB 3.0 card reader. Cards are removed from the camera. Backup only I verify copy and backups of copy are good. For short trips, I will not down load until I get home.
Only longer trips may take 2 card readers just in case. If something go awry (broken cable, lap dies) I don't want to be dead in the water. If I only backup via computer / cable I may not be able to backup on someone else's pc/mac if software to link to the computer does not work.
This brings up an interesting question, when traveling, how do you format external drive? fat 32 so they are compatible on both PC and Mac or NTFS (PC format only) or MAC specific format ?