There are a lot of interesting differences in the basic grid designs and layouts that are a result of the 120 vs 240 voltage differences. Everything from number

There are a lot of interesting differences in the basic grid designs and layouts that are a result of the 120 vs 240 voltage differences. Everything from number of transformers, to distances between substations, to the required line separation and clearance from ground. It all results in fundamental cost differences, that were originally calculated based on density and distances, with US being low density/ large distance and the opposite for the UK. I'm sure there's related consequences with line burial, but I don't know if that's the reason it's so common in the UK.