The reason, IMHO, for the no-cell-phone at the gas pump is the distraction it causes with resulting gasoline spillage. The odds of a cell-phone battery fire are so small that it's forgettable.
When smoking was more prevalent, it was common to see people smoking cigarettes while pumping gas and no one complained.
No judgement here. I think a male 'Karen' is referred to as a 'Ken', per Yahoo. https://www.yahoo.com/lifestyle/male...220326163.html