Lol dirt is going to get in all of it and it's very hard to clean extruded aluminum rails, not to mention how small those wheels were. How's it driven - belts / gears? How often are you going to disassemble and maintain this thing? what's the maintenance schedule like? I would bet it is more demanding than planting a 4x8 raised bed.

That said I still love the project. I don't think the point is to grow plants maximally efficiently at this point, it's a early release of something cool and it's open source.