But if you are at 25k power before renting you could profit around 3 DEC/win in Silver 3. If you play 220 games and have a 50% win rate that is about 330 DEC of pure profit, well above your 90 DEC profit after rental costs to be in Silver 1.
The big difference is the amount of chest you win at the end of season. Not sure if that makes it worth it. I guess it depends on what you value a chest at.