The rotors must be huge to get any lift in that thin atmosphere.
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it does look like they are large in ratio to a light load.
Wikipedia has an article about the Mars Helicopter.
The whole vehicle weighs about 4lbs. A pair of of contra-rotating blades with a diameter of just over 36in spinning 1,900-2,800 rpm. It’s solar powered and each flight is meant to last no more than 3 minutes each. It only carries cameras. Supposedly, it’s being carried beneath the rover. It’ll drop the copter off, drive away, and then the copter will deploy it’s rotors and lift off.
I thought as you did, thinking the blades would look more like paddles. But it looks like they’re looking at rotational speed to create the necessary lift in the thin atmosphere.