Well the pro is that you can store your key in the console, so there is no danger of this getting lost. I had to go through so much trouble, when my company gets old apps from others to renew, cause in most cases, clients dont have the keys and we have to track down the old developer.
The second thing you need them for is aab.
Other than that, I am not sure you get any extras by using it. I prefer storing my own keys, so I don't use this service.