Pros to share with seller about why they should owner finance

I met a couple who bought a 2bd/1bth in Washington near a great area for $104k. It was the property next to their primary residency and they got it just to knock down trees so they could have a better view of the mountains. This was a year ago and they haven't got a tenant. 

They're now selling it and their primary residency and I'm meeting with them about buying it and am going to present seller finance as one of the options. 

I want to make sure I hit all the reasons why it would benefit them. What should I include on that list?

They'll be retiring in 5 years.