The Rally Armor mud flaps have been superb on my car. Installation was an absolute breeze, and they are extremely secure and look awesome.
The main reason I went with these over a hard plastic is due to my car being lowered, I was snapping the hard plastic ones left and right. The rally armor ones will make contact with a driveway or speed bump and just glide over them without issue.
I would imagine in conditions like snow where you will be encountering high points and low points in the road surface, this could be a major pro, as they will slide over the high sections as opposed to digging in to them and either filling up with snow or worse yet ripping off or cracking.
As the above poster mentioned, just like the Tesla OEM design they are a flat surface, so will not accumulate debris, they will just shrug it off. The material Rally Armor uses is slippery as well, which should help even more. I'll likely apply some SiO2 to them to make them hydrophobic to allow for easier cleaning as well after contacting Rally Armor to ensure that SiO2 or a true ceramic coating won't damage the material that they are made of.
Once again I want to reiterate, they look AWESOME. I ran these on my Evo IX for years before I sold it and have always loved Rally Amor mud flap products. I need to get a picture in but I dropped the car off for front PPF and ceramic coating the day after the install. Will try to return with photos when I get the car back, but you can find plenty on the internet. I went with the grey font for my grey car.