Well... I've been reading back and forth about the issues with for instance an instant power loss of the hub and with a possible corrupted DB as a result of this.
Fortunately I live in a country with a very stabile power grid, but with that said it doesn't mean that it cannot happen, especially during summer time with thunder storms that might cause shorter outages. So because of this I bought a dirt cheap power bank/UPS from eBay called GM322 and apparently in my country quite rare power cable for the C4-hub from Lindy.
All was fine and I was happy until I realized that I didn't know how to gracefully shut the hub down, because I do not have any UPS for the router so the network will naturally be down if the power is off. The reason for not having any external power source to the router will be because both of the inconvenience and the non esthetically pleasing due to the fact that that I have three wall mounted ASUS Lyra as mesh-routers.
But... I was pleasantly surprised that the http://hubIP:8080/hub/shutdown actually was working without any connection to the router. This was checked by creating a timed rule and long before the occasion I plainly yanked the ethernet cable out of the hub, lo and behold the action did work!
Next step will be to use a trigger that makes more sense, for instance one of my power reporting Z-wave plugs. Here I might check the mains once every hour or so and if there is no reading or if it differs to normal, the rule will gracefully shutdown the hub.
I can also confirm that the GM322 mentioned above is working perfect when switching the power source off and on without making any impact on the hub at all!