Way I see it is dual investments are essentially cash secured puts and covered calls. If you have usdc or usdt and are okay with purchasing eth at 1800, you’re doing a cash secured put to purchase it at that price. The “premium” of that is the apr earned. Covered call is opposite way, you are okay if you sell eth at 1900 and will earn a premium on the pledged eth. These transactions clearly could be done with limit orders but with a limit order you won’t earn on the funds while waiting.

Auto invest just keeps whichever instrument rolling, collecting premium each day without you having to re-select the option. I’d assume once the contract is exercised (ex. if buy eth at 1800 goes through) it wouldn’t auto invest back the other way. You’d have to go in and select the sell eth level that you desire and again enable auto invest for it