For example, it's well known that EV range decreases by 20-30% in cold weather and a recent study is claiming about the same loss in hot weather. And on long drives you tend to be more heavily loaded than normal, also cutting a few percent off actual range. Further, you need a reserve in case you get stuck on the road for some reason. Also you need a further reserve to ensure you can make it to the next next charger should the next charger be unavailable for some reason. And the advertised ranges are in better-than-average driving conditions at slower-than-average speeds, so you lose another few percent there as well.

All these derates stack which means if you want to ensure low stress in an EV you might have to derate the advertised range 50% or more depending on charger density for long drives when you decide to purchase. ICEs also need derating, but 25% is usually lots and ICEs tend to have much longer ranges to begin with.