That will heat the choke and turn it off if you sit with the key on and the engine not running. Running the choke through the oil pressure switch ensures that the choke will not heat unless the engine is running. You pays your money and you takes your choice. I kind of like being able to turn the choke off by letting it heat with the key on but the engine not running. Just make sure that you sit with the key in the off position if you don't want the choke heating.