The idea is that big cake player, will more likely sell their cake for usdt. When you have a million in cake you won't keep the ones you gained from staking in the pools(about 2000$ a day).
But if we would increase the unstaking fee time, those whales would unstake fewer. Cake would be less volatile and if they take their earnings out before, they would pay 2% fees which increases the burn buy back. Which would make cake less inflationary
We only need the abitrage traders for the farms...