Think of any single
cell of being made up of an infinite number or parallel plates infinitely small. Now you can visualize that if many separate batteries of the same chemistry are placed in parallel that is similar. It has been close to 100 years now of combinational series and parallel batteries being used successfully.
Plates can suffer from local areas of contamination which will "drag" down the rest of the same plate in other areas much the same as a salient single
battery in a bank can drag down others. There is no valid argument for only series or only parallel as long as one is prudent in making the configuration.
The term "golf cart" does not denote any significant advantage. A particular brand and model is more important.
The disadvantage of a series/parallel -string is that more terminals and interconnect cables
are required in a bank than would be for a parallel only bank. This is why most cruising configurations are made up of 12V (for 12V systems) only batteries. The only advantage of using 6V batteries is when a particular battery design physically fits where a 12V battery cannot be found to fit.