2 reasons:
The distribution of rewards is going to change to better reward higher leagues. Right now you get a better ROI having a lot of low league accounts compared to fewer high league accounts. This extra incentive will increase the value of leveling up cards, increasing demand.
"Ghost" cards will no longer contribute to your earnings. The majority of accounts out there utilize only ghost cards and don't buy or rent copies of the cards they are playing (in large part because there is little incentive to level up, as stated above). Needing an actual copy of these cards should significantly increase demand for them.
It will also provide a cap on how many people can play, which will derail inflation IMO. Right now there is virtually no limit to how many people can earn from the rewards pool. Remember, the reward pool doesn't increase just because more people are playing, so more players = fewer rewards for everyone. Especially since they don't need copies of the cards they are playing. Once they need copies, more players will still mean a smaller share of the rewards, but it will also mean more players fighting for a limited supply of cards. Lately we've seen a booming number of accounts but no increase in card value as a result. I think we are in for a major correction there once this hits. Either the accounts drop out leaving more rewards for everyone with cards, or those accounts go buy cards and drive up price.
Summary paragraph: my takeaway is that playing the game is likely to become more profitable for those with good cards, because if the number of players is less, then the reward amounts will be more. Or in the second scenario, the number of players remains the same, but now the value of cards increases because those players need all cards to earn rewards.
Thanks for the response. You are helping very many people.
These changes seem like they're gonna be huge for the game and help the ecosystem better divide rewards between active players. But what I don't get is how ghost cards have contributed to your earnings in any way and how that stops in the new reward system. When I started playing, around 2 weeks ago, I had these ghost cards to use but they couldn't earn me anything as I still needed power. So even though I had lots of cards to play I still needed to buy cards to increase my collection power before I could earn anything.
So my question is, what will happen with these ghost cards? Will they disappear entirely or become unusable in ranked so players would need more cards in their collection to get better rewards?
Anyhow, great video! Thanks for clarifying things around the soft peg!