The warlock gauntlets Xur is selling enable some crazy stuff with a devour build warlock.
Every time you punch an enemy to death, it adds a damage boost stack, up to 5 stacks to your melee damage.
At 5 stacks, you are getting something like a 7.5x multiplier on your damage. This means you are punching things for THOUSANDS of damage. Literally thousands. Each punch is like a hit from a max damage rocket launcher.
With devour, each kill refills your health completely.
The total effect here is that you can become an insane punching dealth machine, one-shotting everything while constantly refilling your health.