There are two main benefits of a higher wattage CO2. One is you can cut faster. You can get more parts cut per day, so you get increased speed.
The second big benefit is cutting thickness or cutting capability. You can cut materials on a big laser that you couldn’t on a small laser. You can cut thicker acrylic, thicker metal, thicker wood. You have increased cutting thickness capability with higher wattage.
-Adam Voigt and Eric Johnson, Kern Laser Systems