At the same time though, if it's structured as a "rent to buy" the buyer is exposed to huge counterparty risk on the part of the "seller". If anyone senior to them, including the county in the case of property tax, forecloses on the house they end up with nothing but an unsecured claim even if they're 2 months from paying the entire amount.If you are in California or another state with anti deficiency laws and the FED jacks interest rates you could be taking a property back worth than what you could sell it for today and you would probably not be able to recover anything else from the buyer. You might a property which has been neglected or "harvested".
This is why I believe buyers should pay a premium when sellers do the financing. Buyers in anti deficiency situations are getting a call option on rising real estate prices for the amount of the downpayment money and whatever premium they pay in interest.
Even if it is a real recorded mortgage, the seller is getting significantly above market interest on what they deem to be a low risk, so their risk adjusted return is pretty high. This is like being able to sell a call option on the S&P 500 for 50% more than the going rate.