I didn't have a car charger for my MM but I have one now. I do a lot of outdoor stuff, camping, fishing.. Etc. There are times where there isn't electrical power except for my car. So yes they are very handy.
I would just stick with a skin that you can put on, there are so many of them and if you want to go all black you can. I only use liquid electrical tape on my freestyle drones because there is no case of any kind and I still use it very sparingly.