Beware the the "fair". Currently, governments are taking in vast amounts through fuel taxes. That will need to be replaced. It wont be an extra fee at registration. Current politics favors use taxes. As the concept of taxing electricity going into cars is a massive cluster of issues (ie the "smart grid" with differemt rates for different uses) the answer will likely be road pricing: a per-mile fee, which could mean manditory tracking. The transition to EVs as fair market actors is not over. It hasnt really begun.

The UK has stated that the current mileage check within the annual roadworthiness test will supply this data.

A clear weakness is that mileage readings can be altered. This used to matter on a smaller scale: dodgy second-hand sales, but now more or less anyone could be considered as potentially incentivised to interfere.

The mileage must remain a changeable field since the recording component may need replacement, for example, after accident damage or to correct a fault in the assembly that recording memory is part of.