What makes owner financing appeal to many borrowers is that they will not have to give a full 20% down payment. In exchange, the lender (aka the property owner/seller) will charge 1 to 2% above conventional mortgage interest. The current mortgage rate is 3.61%. So 5% is reasonable.
If you can get a buyer to pay 20% down, then by all means go for it but many buyers will want to put less.