some people have very little to worry about. In other news the NHS is falling apart, criminal justice is on it rse, the police have lost about 25% of their numbers, people are using foodbanks and homelessness is through the roof but yeah, a comma.
Having written many technical documents concerning plant in heavy industry, and dealing with industrial accidents (including a railway one BTW), I can assure you that punctuation can be very important indeed. Someone unwittingly taking the wrong meaning of something, in a specification or operating instruction for example, could really be a life-or-death matter. Stuff I wrote was peer reviewed (and I peer reviewed other stuff in turn) and possible ambiguities were ironed out in meetings in which wording and its punctuation were often refined at length.
I was taught at school not to place a comma before "and", but my experience in technical writing has instead made me favour the Oxford comma.
As for people having more important things to do, like being a doctor or feeding the hungry, we cannot all run around doing everything. It is more effective to have people doing what they are best at - keeping industrial plant running in my case, in which writing unambiguous specifications and operating instructions is a part.