Google's Ad Network is the largest on the Internet - that's fact. However, creating all the different sized assets that you need to take advantage of all the different slots can be a big effort for your design team and your agency.
Which is where Responsive Display ads come in. It is table stakes now to let the alogrithms and the robots take over and it is no different here. You provide Google your copy and your photos and even video, and it takes that information and does all the hard work for you in terms of the creative.
However, we have found that is the only part you should hand over to the machines. In order to get the best result, being extremely selective in where your ads are shown and what audiences get preferential treatment is just as, maybe even more important, not to have any wasted budget.
We had a client in the B2B space that was running display and had huge view-thru rates but next to no clicks, and it is because it was getting funneled into games on mobile devices where people had to watch before they could continue the game.
So our hot tip - let the robots do the creative, and let the humans that don't work for Google manage where they are shown