The "homebuilt experimental" category has many advantages. Plenty of sport pilots and homebuilders use it.
A person can build something in his garage and be flying it next week if he wants to.
Certification , on the other hand requires millions of dollars with millions of rules administered by millions of bureaucrats . Ever wonder why there are very few new aircraft developed today ? That is why.
I am sure Hill Helicopters intend on gaining certification some day , but in my opinion their entry level experimental category is a clever tactic to get some actual machines built , sold , and flying while the agonizing certification process drags out.
I acknowledge there are not a lot of "wealthy" people who wish to assemble their own Hill Helicopter under factory assist rules .... and then not be able to use the machine for commercial purposes , but we may be surprised how many jump at the chance.
Even the autogyro industry has moved forward by leaps and bounds and many "executive types" have bought them (over $100k) and fly them under experimental rules. One model has a titanium frame and mast and state of the art composite blades. The titanium comes from the same factory that produces Boeing parts , blades come from an established manufacturer.
There is an "experimental" gyroplane and an experimental helicopter that have flown around the world. Single engine (Rotax) , added fuel tanks , and 12 hours over open water.
In my opinion Hill Helicopters are wisely taking advantage of this category .... if they can get enough committed customers they are well on their way .