Updating the SatNav is fine - I usually do it to a SD Card from my computer, then update the SatnNav from the card in the car. I still do not think that the VW updates add charging points, certainly in the UK, to be anywhere as complete as they should be. It is still useful to update the Satnav with the new roads, etc.
However, my point was about getting a full and up to date list of charging points is not easy. There used to be (it is still about) openchargemap but there are a lot of charging networks that do not update it. The likes of PlugShare and ZapMap do not have any useful data export, as openchargemap does, to create a POI list which can be used to install on the Satnav.