Can you let me know which property you're referring to? In any event, there are very few homes that an owner would be willing to finance ... most like to cash out and move on.
In the event we do locate one, you should be aware that most require a large down payment (usually 20% to 25%), the interest rate will be considerably higher (probably 6% or greater ... current bank rates are in the 3.5% range), and you will need to obtain financing to pay off the owner in three to five years (the "balloon"). With homes selling quickly, there doesn't seem to be a reason why an owner would elect to act as the bank ... unless there's something critically wrong with the property (bad foundation, structural damage, etc.).
I hope this explains matters a bit for you. If I can be of further assistance, please feel free to contact me.