When you level-up the arena, it will increase the reward multiplier for crowns. The calculation for merits received also depends on the crowns your team will receive.

Question: @cryptomancer
Does it mean that increasing the arena level will also increase the merits you will received? A lvl10 arena at Tier1 will have more merits compare with a lvl1 arena at Tier1 (assuming same number of wins,losses and total match)