Seems like a price to ensure it is only used when really needed, as opposed to being so cheap people will plug-in even if they are at 75%.
I guess it also helps make the charger available more often, for more users, so in effect makes it more appealing to use an EV if you know you are more likely to be able to charge.
Also with a 7kWh post you need to think about the location, and the longevity of the average stay in the same space if it were a car that can't be plugged in. If you find that people normally stay 45 mins, but would stay 3 hours since they can charge, it is blocking a space that could be used by 4 people over the same amount of time rather than 1.
I think as chargers in cities/towns/car parks etc. become more abundant, you'll find the price will settle, with it going up to start with and then drop down again. I also envisage that councils will enforce caps on their own charging costs over time, and enforce maximum allowed time more strictly with charging stopping automatically, and if you are 15 mins over then you get an automatic charge applied.
So many things that will/can/should happen over the next few years, some will work, others won't, and without data gathering and testing you can't just automatically assume an idea is bad or good, especially when dealing with the general public.