Of course it is your own choice to make, I am somewhat tainted in my attitude as I now have several friends with Bengals which have been diagnosed HCM.
It is easy to be of the mind that this is one of those things which happens to someone else, but the truth of the matter is that someone else may just turn out to be you.
As I said, buying from scanned parents is not going to guarantee you a HCM negative kitten - it is a step in the right direction - but should the worst case happen and you bought from non scanned parents despite being made aware of the risks.. Well that is a scenario I would not wish to find myself in, not that I would be happy in either case of course.
Another thing to consider is what is the ethical thing to do, scanning is the only tool at our disposal to try to better the awful situation the breed is in and by only putting money in the hands of a breeder who scans you make a contribution toward forcing those that don't into changing their ways.
To be honest I do not envy anyone who is contemplating buying a Bengal just now, I really don't think I could do it again knowing what I now know