I just used it in my house and although not my first choice......it's just what I could get in a timely manner. My first choice would be blown cellulose in a house. I used open cell in my house, because I think it's better for a home environment. Less chemicals and less off gassing because it uses water as a blowing agent. It absorbs and releases moisture similar to wood, also conducive to a home environment. In a vehicle the moisture would get stuck between the insulation and metal, causing a rust catastrophe. Closed cell uses HFC's (Hydroflurocarbons) as a blowing agent which means more dangerous off gassing. And not sure what impact that would have in a small space like a vehicle. However, in a van you have to used closed cell. For the most part it resists absorbing moisture and thus you won't have the problem of moisture being trapped between the van wall and insulation. But from what I understand, it's not 100% safe from absorbing moisture and can happen, and if it does it will have an impossible time of trying to release it. IMO it just doesnt seem worth the risks or even needed for vehicle dwelling.
In a vehicle I'd use Polyiso. Seems to be the preferred method out there and does the job quite well.