Nope your correct that's a effective way to dissolve the co2 into your tank. It's known as a very inefficient way of doing that but regards to your question yes that's sometimes used. I'm assuming your using a diy since your looking into this method??
I think a ladder type setup would work better with a small diy.. if you got a big enough diy then a diffuser would be ideal.
FYI: you might wanna add a check valve in between there somewhere just in case something happens so you wont have drawback of water.