Is there a difference between ALobbyBeacons and APartyBeacons?

I am trying to create a small matchmaking system with Beacons and I noticed that there is lobby beacons and party beacons. What is the difference between the two? If I try to make a listen server using Steam’s services, would it matter if I try to initialize one beacon or the other?

Also, with Party Beacons, I am supposed to create a session and then find session and pass it into RequestReservation for the Client Beacon. However, I cannot find any sessions using STEAM, but I can using LAN. It won’t even find a session I created locally. Any ideas on this as well?