Interesting article. Hemp used to be grown in the UK for rope and clothing manufacture, but these days with the link of cannabis, although they are two different types, any grown has to have a licence as far as I know. The article isn't too clear, but it seems to indicate that the same part is used for the hempcrete as would be used for cloth. I suppose if a lot was grown, the better quality stuff could be used for cloth and the poorer for building.
only slightly off topic , straw ( or wood wool ) and cement based stuff can be ok for some things.
if i was going for a long term structure ,stones, ceramics, time tested mortars and maybe the odd bit of reliable metal ( the bronze pin + hot poured lead adhesive thing seems to work but good stainless steels have some prospect of longevity) . any timber and most metal should be "plug n play" if planning for millennia
It looks as if hempcrete isn't strong enough for structural work, but used in conjunction with a wood frame. Probably a good alternative to other infills used that way, and being water permeable, with a good lime rendering, it should make a reasonably long lasting wall. It is all going to be in the framing material so good oak heartwood should last well.