Why Easel halves the latency

Most game engines measure latency as your ping to the server. A ping is a full roundtrip (there and back) to the server. Because Easel uses rollback netcode, Easel games do not need to wait until the inputs are acknowledged by the other player, eliminating half the round trip.

Easel instead measures the average time it takes for the other player to receive an input, and just assumes the input is received without acknowledgement. Unlike other game engines, if it gets it wrong, it is able to rollback and correct itself.

Because only the half the round trip matters, it is effectively like there is a server at the midpoint between all players. Sometimes it is like the server is in a geographically impossible place, like the middle of the ocean. In these cases, players will experience half the latency when playing Easel games compared to other game engines.

Another way to look at it is, people who are twice as far away from each other can play Easel games. All of this is available to every Easel game out of the box, without any additional work. This makes it much easier to grow a community of players and makes Easel a much better choice for making multiplayer games.