My initial thought was that this was allowing individuals to rent out their cars and my reaction was a hard 'oh hell no.' What's the term from the various "my expensive camera /lens was stolen" stories? Voluntary parting? Pretty sure that would apply to your nice car as well.
Having face-to-face interactions with renters is surprisingly effective both at maximising upside and minimising downside.
They then proceed to print off paper forms which they staple other forms to, scan them in, print them off again, fax them to the headquarters before emailing them as well, and print them out a third time just for luck, before finally handing out the keys to the car.
Either the whole industry is unreasonably scared of theft, or theft is an actual problem and they need to do everything that can to keep it low to stay profitable.
I can see why they haven't moved to app-based rentals. It's hard to fax handwritten sketches of your ID card via an app...
They also only have one location in the city where you can get cars, and it's usually much further away than the closest car sharing option.
For longer trips (and one-way rentals which are great for moving city) they are still a good option, but if you need a car for an hour to get some heavy tools from the hardware store they're out.
(The other option would be to borrow a cargo bike which is free from the city, but again only when they're open and requires more travel to and from the place.)
That may just be you. It is most certainly not the case in the US.
I actually wonder how profitable these very short term rentals are on their own. Maybe part of their profitability is long term brand development? Certainly city dwellers like me, who gets by with bicycles and public transport mainly, are exposed much more easily to the experience of driving a nice, modern BMW or Mercedes than they would without these "car sharing" offers.
Enterprise is just as easy and they'll even bring me the car.
You can rent a car2go for an hour to do a big grocery run, that's not economical or practical with avis.
Presumably there's an implied distinction between this model, where people share ownership of their primary car, and the typical rental car model, where people are presumed to be traveling or otherwise renting the car to supplement their existing car ownership.
Not saying it's some brilliant insight, but there is an internal logic to the use of the term.