Might be down to costs.
How much does hosting per account in Ireland compare to USA hosting?
Even if a few pennies/cents, at google's scale - that makes business sense and if they can, they will.
How much does hosting per account in Ireland compare to USA hosting?
Even if a few pennies/cents, at google's scale - that makes business sense and if they can, they will.
Hence the question of actual costs to Google in hosting in say Ireland (staffing, taxes, rates, utility costs, cooling....) compared with another location outside the EU that may very well have cheaper running costs due to many factors.
I hope that clears up why location is a factor now as it related to running costs and if they can save some money, well, they will.
More so if they suddenly free up capacity in a datacenter which has higher costs than some other locations outside the EU. All these details do very much, however small, stack up at the scale of users Google operates with and for the UK, several million is a large chunk of potential savings.