Buying leather supports cruel, torturous, and common industry practices such as branding, castration, tail-docking, ear-punching, extreme confinement, and/or live skinning for sensitive animals -- from cows to horses to seals to alligators to kangaroos to turtles to zebras to elephants. It also supports largely unreported abuses against sensitive animals, such as wanton beatings. Meanwhile, the raising of animals for their skin is extremely energy-intensive, and the leather tanning process itself is incredibly toxic and destructive to the environment.
WARNING: GRAPHIC TRUTH
If "sacred" cows are treated this badly in India...
Here, rescued calves that may now live in peace: