This is a great idea that Splinterlands came up with and I think it makes the accounts themselves more valuable but further make bot accounts less likely to pursue earning rewards.

On the contrary, with this new mechanism to unlock soulbound, very few players will be stupid enough to pay again for the cards they have earned with so much work, and there will be very few cards on the market. After 180 days when all cards are blocked again the bot account owners will start selling those accounts at huge profits. That is to say, if this mechanism is the one that will be imposed for unlocking the soulbound, we are then witnessing the birth of a new source of income for bots. You create an account with $10 and they dedicate themselves to accumulating cards, then when the cards are permanently blocked, probably in a year, they sell the account for 1000% of the investment. All this without needing to unlock the soulbound.