Very interesting
Clever idea, and a fun design exercise. However, other than being able to carry another person, I don't see this bike greatly outperforming a standard bike set up with a basket, rear rack and front and rear panniers. I think it would be more enjoyable to have two bikes, one set up for commuting and general use, then a second as a grocery getter, good hauler. This is assuming one has the space for two bikes of course.