What are the benefits of growing with Co2?

Please use the search function.

There are literally thousands of threads on CO2.

You should start with learning what CO2 does for plants, wiki it.

 

Or instead of creating the response that you did, you could have easily summed it up for him.

To OP: Plants absorb CO2 and produce O2. Adding CO2 can be very beneficial to the environment when done correctly.

-C