This choice of Cash vs Financing is a false premise to begin with.
Anyone with enough disposable income to pay a multi-hundred dollar monthly payment on a vehicle designed solely for recreation and to use maybe 4 or 5 times per year doesnt really need to worry too much about the cost of financing.
The question is cash flow. Not savings.
Let people alone to do as they wish and get off their backs here about what they "Should" do.
Probably a better approach might be to ASK WHY they decided to do something one way or the other. That would be more enlightening and respectful.
(In terms of full disclosure I paid cash for my Gulfstream Innsbruck 33ft TT. and I financed half of my 2016 Dodge Ram Cummins 2500) But what might be more interesting to find out in a post like this is WHY someone does it one way or the other.)