A couple of things shook me about this - firstly I guess is the amount that was up for stealing - 100M just "sitting there" seems crazy - how many other multi-multi millionaires have their wealth just sitting in one bank account? Second scam is the wrong word. A confidence scam originally mean the mark had to bring a suitcase of cash to give confidence to the scammers that he had the means to join their get-rich sche…
By virtue of converting the ETH to AAVE wrapped ETH, they're earning interest by loaning out the underlying ETH. Who is taking out loans and paying interest for ETH I have no idea.
Plus, even without the AAVE wETH, they expect ETHs value to accrue faster than any other asset, so there's no cost to letting the money just sit, as opposed to your USD in savings depreciating over time.