Handlebars come in various lengths, so what is the difference? Bigger riders with wider shoulders prefer wider bars to allow them to stretch out. 

Additionally turning is easier on a wider bar. Therefore city bikes and folding bikes are perfect for wider bars. Keep in mind rise bars are also best for city and folding bikes, because they allow for more adjustability. try a wide bar on your folder, especially if you ride in urban areas with lots of sharp turns, it will make your ride more pleasant.