I think it´s a bad idea. An upgraded cards is 1500 electrums! This reward is too high for pvp.
A good deck building has high rewards.
The system can lead to money accumulation, the rich become richer, the poor become poorer.
Other problems :
- The "win game" cheat. People will become angry, when they lose an upgraded card against cheaters.
And what about desyncs ?
-The problem, people who fear to lose, quit before the last turn ends. How shall the people get or lose cards then,the computer doesn´t see the 2nd player, when the spins come? It makes cheating possible.
-If you lose, you can close, before progress is saved.
-People like jmizzle7 could push smaller players by losing games on purpose.
P.S.
Elements is not poker. And it´s not Duel Monsters (Yu-Gi-Oh).