We shouldn't take away the option for people to buy bonds for $ even if they're on hard mode, you're right.
Have you ever thought about how many bonds do the richest people have? Shar literally just told me he'll own two ecos if there isn't some kind of a limit for that. And how can you not see that it will screw up the eco? You ok? It's about selling the bonds to other hard mode players using the money you got on the normal mode, wtf. Then whats the point of even having a separate mode with a separate eco?