Hosting through Bitmain actually might be alright

Just reading through Bitmains hosting for S21 and it basically says you pay $0 electricity until you have mined the value of your miner + 5%, so you make 5% on USD of what you paid. However once you have mined the value you have 2 options. You can pay the electric bill which is 10c/kw and keep the miner, or you can wipe off the electric bill debt by transferring ownership to Bitmain. If im not missing anything, if BTC mining tanks and it’s not worth keeping the miner, say true value is $2500, then you’d happily use that to wipe away the debt, or it takes an extra $1k in power then what you paid so it would make sense to wipe the debt, But if BTC mining is pumping you could pay the cash out of pocket and keep mining or sell the miner. Sounds like an arbitrage, but it also sounds too good to be true. Am I missing something? Why would Bitmain take the worse end of the deal?