by owner financing, buyer can itemize interest, property tax cost because it is their primary residence. They accumulate equity as they make monthly payment. Also there is less risk to buyer. In rent to own case, if seller has a mortgage, seller may collect rent and stop making mortgage payment, and lose property to foreclosure. Tenant cannot do much about it.
Owner finance is much better than rent to own for buyer side. I would say over 90% of rent to own do not work out in the end. If seller really want to sell, seller finance may be an option. The author obviously did his homework and came up with a win win situation.