You are correct with the 10MB/s, so an ancient Class 10 card will work fine, and a Class 6 is quite likely to work, but modern cards have issues when writing multiple channels, they need time to clear the deleted areas ready for reuse, and to perform their wear levelling, and then they slow down when they get too warm; so modern cards, unlike the old Class X cards, do not guarantee any write speed unless the camera provides a lot of buffering, which dashcams don't like to do, just in case of data loss on power failures.
So the requirement is to choose a Viofo recomended card, not one that claims any particular write speed.
For most people, endurance isn't much of an issue, but cards do slow down with use, so for drivers that spend a lot of time on the road, or if you want 27/7 recording, then an endurance card should stay reliable for longer.