I'm not a financial expert, but I'm pretty familiar with risk management, and they're somewhat related.
As far as I know, there are 2 main kinds of loans, secured and unsecured. Unsecured include credit cards and personal lines of credit. Secured is normally tied to the asset you're buying, but doesn't have to be. I wouldn't suggest mortgaging your home to finance an aircraft, if only because you're going to feel silly if you trash the plane and end up having your house tied up in that debt. Just me. And I don't see someone financing a kit based on the equity of the kit. If you finance an aircraft, there's going to be a required down payment, and I'd bet a requirement for hull loss insurance. So that if you trash the plane, the bank is paid, and you walk away - hopefully that is. If you take out a personal loan or put it on a big CC, you don't have to have the plane insured, but you probably should, because you aren't going to be able to walk away from that unsecured loan easily, assuming you have a home, investments, etc.
So my 2 cents would be to get an aircraft loan if you want to buy an aircraft, and if you buy a kit consider if you're willing to take the risk of financing it. I think the risk of the kit is mostly that it sits in your garage while you try to find time to build it, meanwhile you're paying for it plus interest.
As far as the own/finance argument goes, a rough expression of that is the Archie Bunker quote "You don't buy beer, you rent it." Or, that at the end of the day, we start with nothing, we end with nothing, and in the middle we have toys. Some things can be considered investments, but they all have risk. Ownership is fragile for most things. My close friends with grandparents or great-grandparents from eastern Europe can vividly attest to that.