[sfvisser]

My guess is the author just picked the simplest syntax to parse in order to demonstrate the tech. If it works and shows to be successful you can always write a GHC (or whatever) backend that compiles to this runtime. Maybe come up with some binary IL etc

[hexo]

Or write self-hosting GHC backend that works like HVM does. That would be very neat.

For me, these projects (such as HVM) are great research stuff showing us how to do (or not do) things.