Problem with BEV is that they carry around a huge heavy lump of a battery and only ever have access to 50% of it, they reserve the bottom 30% and top 20% from new to limit the depth of charge and discharge ( depth of discharge or DoD is the killer for batteries, the greater the amount of capacity that gets used and replaced the more the battery gets damaged ) and as the battery ages and the capacity drops the algorithm allows progressively more and more access to this 'reserved' area to try to keep the range of the vehicle near where it should be ( but don't succeed by the reports I have read ) - problem is by allowing greater depth of discharge the battery is damaged progressively more, so a bit of a vicious circle, as the worse the battery gets, the worse it gets. Fast charging also damages battery, which is why the bloke who bought a new leaf sued Nissan as he could only get 60% of claimed range and only fast charge once a day ( he sat on motorway services, mid journey for 3 hours waiting for it to recharge, not the advertised 40 minutes to 80% or whatever Nissan claimed). The range of a BEV is still AFAIK arrived at by traveling steady 50mph on a flat road, motorways and hills can really knock a hole in the claimed figures. The other thing is battery charging is non-linear, so 40 minutes to 80% sounds as though another 20 minutes may get you to 100%, but may well turn into over 2 hours to 100% - people who advertise cars choose their phrasing very carefully and hope people assume the rest
IMHO BEV are maybe OK as a second car ( but an expensive one ), but range anxiety is still a problem.
I have a friend who has a 24kwh Leaf from 2014. His has done just under 50,000 miles and he still has all 12 bars and the last test showed it had 92% battery state of health.
Given the 50% usage that increases as battery ages algorithm that BEV use, how they work out the total degradation is a bit of a mystery......