Do you think climbing would be so much fun if rock felt "warm" when you climbed on it? Warm like plastic?

Your hands like cool things. Rock is a cool thing. Synrock holds are cool things.

When you train hard your hands generate lots of heat. Heat is the enemy. It chaffs your skin and it prematurely fatigues the body. Synrock is good at dissipating that heat from your hands. Synrock has a much higher heat capacity and thermal conductivity than plastic. It can do the job of keeping your hands relatively cool.

What about a cold garage in the winter? Granted you will want some plastic holds to grab when you FIRST start your workout. But at the end of your workout you will find yourself wanting to grab the synrock.