BGP Aggregate route vs Summarizing a route

Hey Guys, got a quick question we are a little confused on.

Background: We are using Azure cloud and we advertise our satellite sites under our BGP statement at our Data Center so that Azure knows to come to our Data Center to reach our satellite sites. These satellite sites are connected to the data center via MPLS or VPN. Keeping that in mind, our BGP list of networks is huge and we have to manually input them under BGP. We had 2 ideas given to us by an engineer at Cisco Live.

1. Use an aggregate route which essentially would summarize all of our routes, say 192.168.X.X/16

2. Or using a summary route as 192.168.X.X/16

Our question is what's the difference between summarizing a network vs using an aggregate address? Or do you guys have a better idea so that we don't have to manually add a statement under BGP every time a new site comes up?