> It's hard to take the non-nuclear Orion seriously ...
It might be a bit early to describe a booster as "non-nuclear" until there's a practical candidate in the nuclear category that meets with public approval. That would be like calling a coal-fired power plant non-fusion-based.
Orion, as a spacecraft name, originally referred to the plan to build spacecraft propelled by pooping nuclear weapons out the back and exploding them behind a gigantic pusher plate. It may not have public approval, but it's quite practical (aside from the bit where you poison the planet and trash every piece of advanced electronics in a thousand-mile radius) and very well known among nerd circles, so it's worthwhile to disambiguate.