Do we need a new word for "business case" when its about the public sector?
Business implies there needs to be profit in it, but in the public sector few activities even cover their costs. What's needed is for the investment to be worthy: to produce overall benefits across the system/network of services/users. I'm not sure what the right language to use is. Ttracing the value of the investment can be tricky, because the benefits of investment might be felt at a different point in the system, so the problem is knowing what and where to measure the change affected by a particular investment.
… and yet it does need to be accounted for somehow. maybe the responsibility of initiatives that invest public money is to show that the investment is valued at different parts of the chain, even if we don't have a good language (yet?) to express it.