This feature benefits virtually only Nordeus; signing the 4 star player will cost you a relatively significant amount of tokens, while signing and then selling the 2 star player will cause other users to spend tokens in bidding for him in the auction market. The amount of virtual money obtained by selling the 2 star players is insignificant compared to the amount that will be needed at the level concerned. There might be a small benefit for teams that have always been on the brink of being in debt for the last few seasons or teams that lack players in their team, but other than that, it does not provide any advantage to the user.
Briefly, not only for this feature but for many other things in this game, Nordeus makes use of its users to make money. That is, the users are indirectly doing a lot of the business work for the company without realising it.