The cuff has become a great detail when assembling your outfit. It changes the appearance of your pants, draws attention to your shoes or allows for a bit of color and expression with coordinated or eye catching socks.
The cuff also adds versatility to your shoe collection. A pair of dressy slip-on driving mocs or stylish oxfords can be dressed down with jeans or khakis by a simple division between the pants and the shoe. It can also be used to allow a more casual shoe, like a nice pair of Jack Purcells, to compliment a nice pair of slacks and a sports coat. The look can also be used with lace-up boots for the same effect.
Often times, just having a shorter pair of pants can make it appear your tailor messed up the inseam, but with a simple cuff the look is achieved and the pant length can remain unaltered. This allows for more diversity in your wardrobe and makes the most out of your shoes, socks, and certainly your pants.
(Image credits: birchbox.com and thexstylez.blogspot.com)