This is a tricky subject. Most fuels require a certain amount of processing to be ready for use. Fossil needs refining, H2 needs extracting and transporting, even electricity needs to be generated (try saying it’s greener when the grid for some countries is still mostly fossil powered). So, if E fuels can be produced cleanly then I can’t see a reason why that shouldn’t be allowed, at least to keep the classics running. However, if it requires some massive amount of energy to create a few litres, for the inefficiencies of the combustion engine to then waste more of that energy, questions have to be asked.
In reality, the goal will be that private ownership of cars will decline to a luxury item, with either public transport (cleaner and cheaper than currently available) or some subscription basis will be better for the planet. I read a stat somewhere that cars spend more than 80% of their day unused. All that production to build something, fuel it and then it sits at home, drives for an hour (or so) to sit at the office to drive for another hour to sit waiting for the next day seems somewhat wasteful but that’s what many of us expect currently (me included) and removing wasteful ownership and use of resources will, eventually, become the priority.