Sometimes it causes confusion because "participation" can be interpreted differently. In the game it means do 1 single encounter and you have participated enough to get full rewards.
most people however do not call 1 encounter a "meaningful participation" and they will often complain about people getting rewards for "not participating"
The spire works differently, there you have to participate every step of the way to receive all rewards, if you participate less you get less rewards. It increases the motivation for everybody to participate more.