Depends on how often a person needs to go out and service those parts. With a drone fleet, they can be serviced from a central location. If one dies in the field, then they can replace it with a backup while someone goes out to retrieve the downed drone.
Cost-wise I have no idea which side this works in favour of, but the idea that "a hair dryer and a $10 cellphone camera" is cheap so therefore better ignores things like maintenance costs. Having a person constantly going out into the field to service these parts will definitely cost more than the parts themselves (and is not a cost you can ignore).
I think you're seriously overestimating the reliability of drones and at the same time underestimating the reliability of hair dryers. Also, ignoring for a moment that no commonly known type of drones would work in the martian atmosphere, stationary solutions have much more leeway for building it to NASA standards - better coils, more solder at joints, etc. I'm willing to bet that a simple blower hooked up to the energy storage and a timer mechanism could work without intervention for a hundred years or more - if made in the way they did it 40-80 years ago, as opposed to today, where all consumer devices are as crap as producers can get away with, on purpose. Contrast with (hypothetical) service drones, when every gram of additional reliability is cutting into the flight time.
As for what kind of drones could work on Mars... well, leafblowers on service rails or on wheels are the only things I can come up with that make sense. Magnetic field flying is probably too energy-intensive, and quadcopters won't work in martian atmosphere.
EDIT: I think the Sahara and Mars threads got mixed up...
Cost-wise I have no idea which side this works in favour of, but the idea that "a hair dryer and a $10 cellphone camera" is cheap so therefore better ignores things like maintenance costs. Having a person constantly going out into the field to service these parts will definitely cost more than the parts themselves (and is not a cost you can ignore).