I have a handicapped parking placard for my vehicle due to having neurologic and orthopedic conditions that on some days really limit my ability to walk. On the days I can walk well, I don't use it. On the days I don't walk well, I use it. Thankfully for me the days I don't walk well during the spring, summer and fall are pretty few and far between.
During the winter though, that's another story. It infuriates me when I see someone get out of a vehicle after parking in a handicapped spot and watch them jog/run into the store or are smoking, fat/obese etc.. If you're handicapped FFS take better care of yourself! Fat isn't a handicap! It's a freaking choice!
I know a guy like you. He has a prosthetic leg since birth. He used to drive a five speed, skis, bikes etc. but he also has a handicap option plate for if he needs it