The correct answer is yes and I will die on this hill. If you have a particularly long sentence you sometimes need to break it up with commas to help the pacing, and adding a comma before an ‘and’ provides an alternative softer form of the spacing normally provided by a semicolon. It also helps separate certain ‘and’s if you have a few close together in the sentence, like when you want to make a list and then make a follow-up point. “Today I ate this, that, this’n, that’n, thus’n and thi’us’n, and in my opinion this’n is the best.”