[Joe Ford]

It can damage the ESC if you're using it to try and reduce current in a system that is over the max the system will handle. Other than that it's because of a little more heat that is being generated from switching losses. That's about it. As long as you have a proper setup that you know is well within the limits of the system you shouldn't have any issue. I personally do not limit it...I just use the right kv motor, gear it correctly for the top speed I want, and put the right cell count battery in it.