> What value does this add over stocking various drinks, in containers, in a refrigerated case with no machine?

You can market it as "fresh".

if it comes out of a bag, it's not fresh.

Of course not, but you can still market it that way.

Basically those units are a great idea, but to keep costs down they only serve one at a time. If that could change to each unit even serving 2-3 the bottlenecks would ease, and you could also consider blended approach in which you have the standard 4-6 nozzle dispenser and one or two freestyles. After all some people really have no interest in anything other than straightforward Cokeor whatever else.

I don't see a lot of differences between the self serve milkshake machines in gas stations and this proposed self serve juicer.