For a casual spenders who buy a few high gems cost contents against money from time to time, this game will end up being more expensive as you suspected.
DL is cheaper for 100% F2P forever players. But it's more expensive for anyone else like for:
"casual players that spend a few bucks here and there"
+
"3rd category that buy literally everything"
In short: this game is harsh with f2p players, most decks need cards from several different boxes and gems are very scarce, it will take months before they can build the deck they want.................thing that can be solved only with real money