The problem with homebuilt helicopters is that the very market they are aimed at - those who can't afford to fly something more expensive - are those who shouldn't be flying them. Only because they don't have the experience.
I know of at least one person who taught themselves to fly a helicopter, but he had a great deal of time to do it over and a great deal of discipline.
A small light helicopter can kill you just as quickly and easily as small light airplane - and we have plenty of experience of that. The same safeguards and rules as the light homebuilt, kit built people use should be used on light helicopters.